Transcript Ultimate AP BIOLOGY REVIE

Isotopes: Isotopes are atoms with the same
number of protons but differ in number of
neutrons; e.g., a carbon atom has six protons
but may have more or less than usual six
neutrons
 Valence Shell: Outer shell of an atom. Atoms
with few electrons in their valence shell tend
to have more free electrons since these
valence electrons are more loosely bound to
the nucleus.
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Ionic Bonds: Ionic bonds form when electrons are
transferred from one atom to another. Losing or
gaining electrons, atoms participating in ionic
reactions fill outer shells, and are more stable.
Covalent Bonds: Covalent bonds result when two
atoms share electrons so each atom has octet of
electrons in the outer shell. . Structural formulas
represent shared atom as a line between two atoms;
e.g., single covalent bond (H-H), double covalent
bond (O=O)Three dimensional shape of molecules is
not represented by structural formulas but shape is
critical in understanding the biological action of
molecules: action of insulin, HIV receptors, etc.
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Hydrogen Bond forms between…
› slightly positive hydrogen atom of one
molecule and slightly negative atom in
another or the same molecule.
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pH is a measure of…
› How acidic or basic a solution is.
 Acidic Solution has more H+ ions
 Basic Solution has more –OH ions
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Buffer is
› keep pH steady and within normal limits in
living organisms..
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Isomer is…
› Are molecules or molecular compounds that
are similar in that they have the same
molecular formula, however have different
arrangements of the atoms or groups of
atoms (functional groups) involved.
› Example: Fructose and glucose (C6H12O6) –
same molecular formula but different
arrangements
› -OH –
› C=O
› -COOH
› -NH2
› -SH
› -OPO3
Hydroxyl
Carbonyl
Carboxyl
Amino group
Sulfhydryl group
Phosphate group
 Hydrolysis
Reaction
› Reaction that breaks down compounds by the addition of H2O
 Dehydration
synthesis reaction
› Reaction in which two compounds are brought together with H2O
released as a product
 Endergonic
reaction
› A reaction that requires the input of energy to occur
 A+B+energy C
 Exergonic
reaction
› A reaction that gives off energy as a product
 A+BEnergy +C
 Redox
reaction
› A reaction involving the transfer of electrongs
General formula for monosaccharides
are CnH2nOn
 Example: C6H12O6 (Glucose)
 Simple Sugar
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› Function: Sugar found in Nucleic Acid
› Glucose: Sugar for the body
› ATP: Cell Energy
Polysaccharides: Carbohydrate containing 3
or more monosaccharides
 Storage form of energy
 Structural material in and around cells
 Difference between

› Glycogen: Glucose molecules linked together
(animal energy storage)
› Starch: Glucose linked together (Plants energy
storage)
› Cellulose: composed of glucose molecules –
formation of cell walls
› Chitin: Glucose molecules joined togetherArthopods exoskeleton
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Structural Components of the following…
› Fats: Lipids made by combining glycerol and
three fatty acids. Used as long-term energy
stores in cells
› Phospholipids: is a lipid formed by combining a
glycerol molecule with two fatty acids and a
phosphate group; bilayered structure –
component in cell membrane
› Steroids: are lipids composed of four carbon
rings that look like chicken wire.
 Examples: Cholesterol, sex hormones
Cholesterol
Testosterone 

Protein Chains:
› Primary Structure: Sequence of amino acids to
form a polypeptide chain (protein)
› Secondary Structure: 3-D arrangement of a
protein caused by hydrogen bonding at regular
intervals along the polypeptide backbone
› Tertiary Structure: 3-D arrangement of protein
caused by interactions among the various R
groups of the amino acids involved.
› Quaternary structure: The arrangement of
separate polypeptide “subunits” into a single
protein

Enzymes are proteins that act as organic
catalyst (speed up reaction by lowering
the energy (activation energy) needed for
the reaction to take place but are not used
up in the reaction.
Induced-fit model: of enzyme-substrate
interaction describes the active site of an
enzyme as specific for a particular substrate
that fits its shape.
 Allosteric enzyme: An allosteric enzyme is an
enzyme that contains a region to which small,
regulatory molecules ("effectors") may bind in
addition to and separate from the substrate
binding site and thereby affect the catalytic
activity. On binding the effector, the catalytic
activity of the enzyme towards the substrate
may be enhanced, in which case the effector
is an activator, or reduced, in which case it is
a de-activator or inhibitor
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Four ways enzymes can be affected:
› Temperature
› pH
› Concentration of the substrate
› Concentration of the enzyme involved
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Prokaryotic: Simple cell
› No nucleus
 Nucleoid : Genetic material
› No membrane bond organelles
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Eukaryotic is more complex
› Nucleus
› Membrane bound organelles
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Ribosomes: protein synthesis
Smooth ER: lipids synthesis, detoxification, and
carbohydrate metabolism
Rough ER: Ribosome are attached – proteins are
produced
Golgi apparatus: proteins, lipids, and other
macromolecules sent to the Golgi to be modified by
the addition of sugars and other molecules to form
glycoproteins – products form vesicles
Mitochondria: powerhouse—ATP is made here
Lysosome: Digestion center
Nucleus: Control center, contains DNA (genetic
material)
Vacuole: Storage (Plants have a larger structure)
Chloroplast: Plants only – site for photosynthesis
Fluid Mosaic Model: the membrane consist
of a phospholipid bilayer with proteins of
various lengths and sizes interspersed with
cholesterol among the phospholipids.
 Two types of proteins in the cell membrane:

› Integral proteins: implanted within the bilayer
and can extend partway or all the way across
the membrane
› Peripheral proteins: such as receptor proteins,
which are not implanted in the bilayer and are
often attached to integral proteins of the
membrane

Difference between…
› Diffusion: movement of molecules down their
concentration gradient with the use of energy
(area of higher concentration to lower
concentration)
› Osmosis: movement of water down its
concentration gradient (passive diffusion). Going
from a higher water concentration to area of
lower water concentration
› Active Transport: is the movement of a particle
across a selectively permeable membrane against
the concentration gradient (Going from low to
high concentration)
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Hyperosmotic (Hypertonic): moving of
water from a high solute in the
environment to area of low solute
concentration to environment. The water
will move out of the cell
60%
water
40%
solute
40% water
60% solute
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Hypoosmotic (hypotonic): Is when the
solute concentration is more in the cell
than outside the cell. The water will
move in of the cell
40%
Water
60%
Solute
60% water
40% solute
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Isosmotic (Isotonic): The solute and water
is on the same on both sides
50% solute
50% water
50% solute
50% water
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Phases of Mitosis:
› Prophase: Nuclear envelope disappears,
chromatids appear, centrioles moves to
poles
› Metaphase: chromosomes move toward the
center –Spindle are attached to the
centromere
› Anaphase: Chromatids separate and move
toward the poles
› Telophase: Chromatids move toward each
poles, nuclear envelope reappears,
cytokinesis begins
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Mitosis: is the dividing of body cells
› Daughter cells will have the exact number
chromosomes as the parent cells
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Meiosis : is the dividing of sex cells
› Daughter cells will have half the number of
chromosomes as the parent cells
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Cell cycle includes:
› Interphase: the stage that prepares the cell
for the cell division
› Mitosis: is the division of the nucleus
› Cytokinesis: division of the cytoplasm
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This is the way in which the cell has a
type of check and balance system that
ensures the cell is correct
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Checkpoints
Density-dependent inhibition
Growth Factors
Cyclin and Protein kinases
You may want to go back and look over
this information
Mitosis
Meiosis
Number of cells
2 diploid cells
4 haploid cells
Crossing over
No
Yes-Prophase I
Number of phases
1 (IPMATC)
2 (IPMATC & PMATC)
No Interphase in the
second phase
Types of cells
Body (Somatic) Cells
Sex (Gamete) Cells
Number of
chromosomes
Same number of
chromosomes as the
parent cell
Diploid
Different number of
chromosomes as the
parent cell
Haploid
Genetics
Genetically Identical to
the parent cell
Genetically different to
the parent cell
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The difference between meiosis I and
meiosis II is that the cell does not go
through interphase (Chromsome
replication) during meiosis II. This will
allow the cells to have half the number
of chromsomes (haploid).
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Crossing over is when the homologous
chromosomes match up during
prophase I of meiosis, complementary
pieces from the two homologous
chromosomes wrap around each other
and are exchanged between the
chromosomes.
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Three parts to a nucleotide are…5 carbon
sugar, phosphate, and nitrogen base
› Serves as a puzzle piece to the nucleic acid
strand (RNA or DNA)
Adenine and guanine are purines
 Cytosine and Thymine are pyrimidine
 Base pairing states that Adenine will pair up
with thymine and Cytosine will pair up with
Guanine (Apple=Tart and Go=Cart)
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DNA replication occurs during the S-phase
(interphase), semiconservative (which the one
strands serves a template)
Built in the 5’ to 3’ direction
DNA helicase will unzip the strand by breaking
the hydrogen bonds producing a replication
fork
Specific regions along DNA strand serve as
primer sites that signal where replication should
originate
DNA polymerase – enzyme superstar binds to
the primer site and adds nucleotides to the
growing DNA chain (will only add to the 3’ end)
The DNA polymerase only being used on the 3’
creates a problem which only allows the one
strand to add nucleotides this is known as the
leading strand.
 The other strand is known as the lagging strand
 The lagging strand consist of tiny pieces called
Okazaki fragments, which are later connected
by an enzyme called DNA ligase to produce the
completed double stranded DNA molecule
 RNA primer allows for the RNA strand to bind to
the DNA strand (this occurs during replication)

DNA can only stay in the nucleus so it
must send its instructions out to the cell.
This is done by the second nucleic acid
(RNA).
 Because DNA and RNA have very similar
language it allows it to be
accomplished.
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Transcription: is the process of taking
DNA to a RNA strand (Occurs in the
nucleus)
› This is done by three steps:
 Initiation: When RNA polymerase attaches to
the promoter region of a DNA strand
 Elongation: a promoter region recognition site
that shows the polymerase where transcription
will begin. Once RNA polymerase works by
adding the appropriate RNA nucleotide to the
3’ of the growing strand
 Termination: tells the polymerase should
conclude
Translation: process by which the mRNA
specified sequence of amino acids is lined up
on a ribosome for protein synthesis (mRNA 
DNA)
 Each amino acid carries a specific
nucleotides/codes (codon)
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› Start Codon: AUG
› Stop Codon: UAA, UAG, UGA
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Anticodon is the complementary to the
codon (tRNA) that has been incorporated
into the growing protein
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Define the following:
› Promoter: a base sequence that signals the start
site of genes transcription; this is where RNA
polymerase binds to the begin the process
› Operator: a short sequence near the promoter that
assists in transcription by interacting with regulatory
proteins
› Operon: promoter/operator pair that services
multiple genes
 Well known example is the lac operon
› Repressor: protein that prevents the binding of RNA
polymerase to the promoter site
› Enhancer: DNA region also known as “regulator”
that is located thousands of bases away frm the
promoter
› Inducer: a molecule that binds to and inactivates a
repressor
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Structural Gene: one that specifies the
amino acid sequence of a polypeptide
chain
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Energy is…
› The ability to do work
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Entropy is the measure of amount of
energy that is not available for work
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ATP power cellular work the energy
currency of cells (adenosine triphosphate)
Functions:
1. CHEMICAL WORK - Supplies energy
needed to make macromolecules that
make up the cell (and organism)
2. TRANSPORT WORK - Supplies energy
needed to pump substances across the cell
membrane
3. MECHANICAL WORK - supplies energy
needed to make muscles contract and
other cellular parts to move (flagella)
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Glycolysis
› a) a ten-step process that occurs in the cytoplasm
b) converts each molecule of glucose to two
molecules of pyruvic acid (a 3-carbon molecule)
c) an anaerobic process - proceeds whether or
not O2 is present ; O2 is not required
d) net yield of 2 ATP per glucose molecule
e) net yield of 2 NADH per glucose (NADH is
nicotine adenine dinucleotide, a co-enzyme that
serves as a carrier for H+ ions liberated as glucose
is oxidized.)
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Kreb Cycle –occurs in the mitochondria
› a) occurs in the inner mitochondrial matrix
b) the acetyl group detaches from the coenzyme A and enters the reaction cycle
c) an aerobic process; will proceed only in the
presence of O2
d) net yield of 2 ATP per glucose molecule (per 2
acetyl CoA)
e) net yield of 6 NADH and 2 FADH2 (FAD serves
the same purpose as NAD)
f) in this stage of cellular respiration, the oxidation
of glucose to CO2 is completed
› GO BACK AND LOOK AT YOUR CYCLE
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Electron Transport System – occurs in the
mitochondria
› a) consists of a series of enzymes on the inner mitochondrial
membrane
b) electrons are released from NADH and from FADH2 and
as they are passed along the series of enzymes, they give
up energy which is used to fuel a process called
chemiosmosis by which H+ ions are actively transported
across the inner mitochondrial membrane into the outer
mitochondrial compartment. The H+ ions then flow back
through special pores in the membrane, a process that is
thought to drive the process of ATP synthesis.
c) net yield of 34 ATP per glucose molecule
d) 6 H2O are formed when the electrons unite with O2* at
the end of electron transport chain. [* Note: This is the
function of oxygen in living organisms!]
Glycolysis occurs in the cytoplasm
 Kreb Cycle occurs in the mitochondria
 Electron Transport Chain occurs in the
mitochondria
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Chemosismosis: electrons are released
from NADH and from FADH2 and as they
are passed along the series of enzymes,
they give up energy which is used to fuel
a process called chemiosmosis by which
H+ ions are actively transported across
the inner mitochondrial membrane into
the outer mitochondrial compartment.

Photophosphorylation: ATP a second
product made during the light reaction
Fermentation: an anaerobic respiration in
which glucose is broken down to pyruvate
during glycolysis. There is only a net gain of 2
ATP. There will be no Kreb Cycle or Electron
Transport Chain
 Two types of Fermentation:

› Lactic Acid Fermentation: The production of
lactic acid without oxygen
 Examples: Milk products and muscles being oxygen
deficient
› Alcohol Fermentation: The production of ethyl
alcohol and carbon dioxide
 Examples: Yeast (Bread and Alcoholic Beverages)
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Two parts to photosynthesis are:
› Light (light dependent) reaction: Occurs in the
thylakoid membrane(contains chlorophyll)
 Inputs to the light reactions are water and light
 Products: ATP, NADPH, and O2
 Oxygen produced in the light reactions comes from H2O
and not CO2
› Light Independent Reaction (dark reaction): Occurs in
the stroma
 Inputs into the Calvin cycle are NADPH, ATP, and CO2
 More ATP is used than NADPH creating a need for cylic
photophosphorylation to create enough ATP for reaction
 The carbon of the sugar produced in photosynthesis
comes from the CO2 of the Calvin Cycle
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Transpiration is the process of water
evaporating out of the leaves. When the
water goes out of the leaves the water
the other parts of plants replace the
water through the process known as the
Cohesion Tension Theory

Most photosynthesis takes place in the
mesophyll portion of the leaf
Aneuploidy: The fusing of an abnormal
gamete with a normal one can lead to the
production of offspring with an abnormal
number of chromosomes
 Polyploidy: a condition in which an
individual has more than the normal
number of sets of chromosomes
 Structural Alternations of chromosomes are
mutations. Chromosomal mutation which
include inversion, deletion, duplications,
translocation
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What is the difference between linked
and unlinked genes?
› Linked Genes: group of genes on the same
chromosome
 If genes are close enough then there is a
higher probability of crossing over
› Unlinked Genes: Genes that are not on the
same chromosome
 Only together if the Law of Independent
Assortment (Mendel’s Law)
Restriction Enzyme are enzymes that cut DNA
at specific nucleotide sequence.
 Gel Electrophoresis is a technique used to
separate and examine DNA fragments. This is
when restriction enzymes are used and then
separated by electrophoresis. The pieces of
DNA are separated on the basis of size with
the help of an electric charge. This
technique can be used to sequence DNA
and determine the order in which the
nucleotide appear.
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Gel Electrophoresis can be used in forensics.
This technique require the use of Restriction
fragment length polymorphism (RFLP). DNA is
specific of each individual and when it is
mixed with restriction enzyme, different
combination of RFLPs will be obtained from
person to person
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Polymerase Chain Reaction (PCR) can
be used during Gel Electrophoresis but
can also be used to sequence DNA
› PCR will amplify the gene to be studied
› PCR will allow scientist to study genetic
disorders and amplify trace amounts of DNA
found at crime scences.
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Applications of DNA technology
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Recombinant DNA: contains two or more different
sources
› Cloning: slow process by which a desired
sequence of DNA is copied numerous times
Gel Electrophoresis: technique used to
separate DNA according to size
(small=faster). DNA moves from: - to +
 Polymerase Chain Reaction (PCR): produces
large quantities of sequence in short amount
of time

Mutations: Genetic Mistakes
 Three types of muations are:
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› Gene Mutation: Substitutes one bases for another
 This can include insertion, deletion, and point
mutations
› Chromosomal Mutation: The entire chromosome is
messed up
 This includes inversion, duplication, translocation,
deletion
› Frameshift Mutation: either a base is added or
deleted which causes a change in the reading
frame
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Three causes of mutation:
› Radiation : X-rays and gamma waves
› Viruses
› Random: Age is one example– if a woman
pregnant over 40 has a greater chance for
Down Syndrome
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Difference between Viruses are protein
coat, shape (popcorn ball compare to
Apollo lunar lander), and Nucleic acid
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Viral Reproduction
› Lytic cycle = reproduction occurs, cells burst
› Lysogenic cycle = reproduction does not
immediately occur (dormancy)
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Hardy-Weinberg Conditions
› No mutations
› No gene flow (immigration or emigration)
› No genetic drift (populations must be kept
large)
› No natural selection (All organisms have the
ability to survive and reproduce)
› Random Mating
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Hardy Weinberg equation
p2 + 2 pq + q2 = 1
p2
2pq
q2
Homozygous Dominant
Heterozygous Dominant
Homozygous Recessive
p. 144-145 – you may need to go back how
to answer Hardy-Weinberg equation
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Prezygotic barriers:
› Behavioral Isolation: Different courtship rituals
› Temporal Isolation: Reproduces at different
times
› Mechanical Isolation: reproductive structures
that does not allow reproduction
› Gametic Mortality: Inability between sperm
and egg
› Ecological Isolation: potential mates that
can reproduce but are not in the same area
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Postzygotic barriers: feterilization takes
place forming a hybrid
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Allopatric Speciation: inbreeding ceases
because some sort of barrier separates a
single population into two (an area with
no food, a mountain, etc.). The
populations evolve independently, and if
they change enough, then even if the
barrier is removed, they can not
interbreed
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Sympatric speciation: Interbreeding
ceases even though no physical barrier
prevents it.
› Two several forms
 Polyploidy: a conditions in which an individual
has more than the normal number of sets of
chromosomes
 Balanced polymorphism: this condition can lead
to speciation if two variants diverge enough to
no longer be able to interbreed
Microevolution: Evolution on a species
level
 Macroevolution: Evolution on a large
scale
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Genetic Drift:
1. Genetic drift refers to changes in allele
frequencies of a gene pool due to
chance, more often in small populations
2. Genetic drift occurs when founders
start a new population, or after a
genetic bottleneck with interbreeding.
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Gene Flow:
1. Gene flow (gene migration) is the movement
of alleles among populations by migration of
breeding individuals.
2. Gene flow can increase variation within a
population by introducing novel alleles
3. Continued gene flow decreases diversity
among populations, causing gene pools to
become similar.
4. Gene flow among populations can prevent
speciation from occurring.
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Fitness: Describe the ability of an
organism to survive and reproduce
(produce fertile offspring)
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Natural Selection: The ability of the
organisms to survive and reproduce
› Three conditions of natural selection
 Variation: a population must exhibit phenotypic
variance –difference between individuals
 Heritability: if a trait cannot be inherited, it
cannot be selected for or against
 Differential reproductive success: measure how
many offspring you produce that survive relative
to how many the other individuals in your
population produce
Protist is a eukaryotic
 Autotrophic or heterotrophic
 Multicellular or unicellular
 Mostly asexual
 Mostly aquatic
 Motile or nonmotile
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Ex: Euglena, Amoeba, Paramecium, Algae, Slime Molds
The domain is larger than the kingdom on the
hierarchical level of classification.
 Domain is based on molecular classification
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› Three domain system:
 Archae– no nucleus (prokaryote), cell wall without
peptioglycan, lives in extreme environment
 Bacteria- No nucleus (prokaryote), cell wall with
peptioglycan, all other bacteria
 Eukarya- Nucleus (eukaryote), some with cell wall,
motile/nonmotile
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Six Kingdoms
› Protista: Heterotrophic or Autotrophic
 Unicellular or Multicellular
 Mostly aquatic
 Mostly asexual
 Motile or Nonmotile
 The endosymbiosis theory explains how organisms
developed organelles
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Fungi
› Heterotrophic
› Unicellular or Multicellular
› Mostly terrestrial
› Asexual or sexual
› Nonmotile
› Important decomposers in the environment
› Ex: Mushrooms, molds, yeasts
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Plantae
› Multicellular
› Autotrophic
› Mostly terrestrial
› Asexual or Sexual
› Nonmotile
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Animal
› Multicellular
› Heterotrophic
› Terrestrial and Aquatic
› Sexual (a few are asexual)
› Motile (a few are nonmotile--sessile)
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Archaebacteria
› Prokaryotic
› Lives in Extreme Environments
› Cell wall made up of without
peptioglycan
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Eubacteria
› Prokarytic
› Cell wall made up of peptioglycan
› Normal Bacteria
Photoautotroph: An organism capable of
synthesizing its own food from inorganic
substances using light as an energy source.
 Chemoautotroph: An organism (typically a
bacterium or a protozoan ) that obtains
energy through chemical process, which is
by the oxidation of electron donating
molecules from the environment, rather than
by photosynthesis.
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Chemoheterotroph: An organism
deriving energy by ingesting
intermediates or building blocks that it is
incapable of creating on its own.
 Photoheterotroph: An organism that
depends on light for most of its energy
and principally on organic compounds
for its carbon.
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Eumetazoa: tissues and organs present;
nervous system with neurons
 Acoelomate: no body cavity; body
double-walled sac surrounding digestive
cavity; single opening to outside;
characteristic of flatworms
 Pseudocoelomate:no body cavity;
body double-walled sac surrounding
digestive cavity; single opening to
outside; characteristic of flatworms
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Coelomates: have body cavity
 Protostomes: Mouth develops first
 Deuterostomes: Anus develops first
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Protostome – mouth develops first
Deuterostome – anus develops first
Ectoderm – outside layer, skin
Mesoderm – middle layer, muscles
Endoderm – inside layer, gut
Coelom – body cavity
Pseudocoelom - partial
body cavity
Radial Symmetry Body parts arranged in
a wheel
Bilateral Symmetry –
right and left sides
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Three parts to a plant include
› Roots
› Shoots
› Leaves
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Three basic tissue include
› Ground tissue: that makes up most of the body of
the plant, is found between the dermal and
vascular tissue. It can be divided into three cell
types: collenchyma, parenchyma, an
dsclerenchyma
› Vascular tissue:
 Xylem: support structure that strengthens the plant
and functions as a passageway for the transport
water and minerals from the soil
 Phloem: Function as the highway for plants in the
assisting of sugars from one place to another.
› Dermal Tissue: provides the protective outer
covering for plants.
 Skin of the plant is its epidermis
 Within the epidermis is guard cells which control the
opening and closing of gaps called stomata –which is
vital to photosynthesis.
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Alternation of generation: Plant life cycle,
so named because during the cycle,
plants sometimes exist as a diploid
organism and at other times as a haploid
organisms.
Primary Growth: Occurs in the apical
meristem which is the region that
lengthens the plants.
 Secondary Growth: Occurs in the lateral
meristem which causes the plant to
increase in width

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Transpiration: Is the process of moving water
through the plant. The water is removed from
the plant through evaporation out of the
leaves. Transpiration creates a negative
pressure in the leaves and xylem tissue due to
the evaporative loss of water. Water
molecules display molecular attraction
(cohesion) and other water molecules, in
effect creating a single united water
molecule that runs the length of the plant.

Translocation: the transport of carbohydrates
through the phloem. The movement of the
sugar into the phloem creates a driving force
because it establishes a concentration
gradient. The gradient leads to the passive
diffusion of water into the phloem, causing an
increase in the pressure of these cells.
Xylem: support structure that strengthens
the plant and functions as a passageway
for the transport water and minerals from
the soil
 Phloem: Function as the highway for
plants in the assisting of sugars from one
place to another.

Abscisic acid: “babysitter hormone” It
makes sure that seeds do not germinate
too early, inhibits cell growth, and
stimulates the closing of the stomata to
make sure the plant maintains enough
water.
 Auxin: (Important AP Biology exam
hormone selection) – elongation of stems,
and plants a role in phototropism and
gravitropism

Cytokinins: promotes cell division and leaf
enlargement. Supermarkets use this to keep
veggies of fresh. Fountain of youth hormone
 Ethylene: Initiates fruit ripening and causes
flowers and leaves to drop from trees
 Gibberellins: Stem elongation. Think Grow
when comes to this hormone. It is also
thought to induce the growth of dormant
seeds, buds, and flowers


Phototropism: plant’s growth response to
light. Auxin is the hormone in charge of
stem elongation here. The stem
elongation occurs at the apical
meristem

Photoperiodism: the response by a plant
to change in the length of the day.

Short-day plants: Exposure to a night longer
than a certain number of hours.
› Flowering: end of the summer to end of the winter
 Example: Poinsettas

Long-day plants: exposure to a night shorter
than a certain number of hours
› Flowering: Late spring to early summer
 Example: Spinach

Four major tissue in animals include:
› Epithelial: is made of closely-packed cells
arranged in flat sheets. Epithelia form the
surface of the skin, line the various cavities and
tubes of the body, and cover the internal
organs.

Muscle: Three kinds of muscle are found in
vertebrates:
› Skeletal muscle is made of long fibers whose
contraction provides the force of locomotion and
other voluntary body movements.
› Smooth muscle lines the walls of the hollow structures
of the body, such as the intestine, urinary bladder,
uterus, and blood vessels. Its contraction, which is
involuntary, reduces the size of these hollow organs.
› The heart is made of cardiac muscle.

Connective Tissue
› The cells of connective tissue are embedded in a
great amount of extracellular material. This matrix
is secreted by the cells. It consists of protein fibers
embedded in an amorphous mixture of proteinpolysaccharide ("proteoglycan") molecules.
› This includes: Cartilage, bone, ligaments, tendons,
adipose tissue

Nerve: Nerve tissue is composed of nerve cells
called neurons and glial cells.
› Neurons are specialized for the conduction of
nerve impulses. A typical neuron consists of a cell
body which contains the nucleus; a number of
short fibers — dendrites — extending from the cell
body a single long fiber, the axon.

Ectoderm: Tissue that covers the body
coverings.
› Forms the central nervous system, the lens of
the eye, cranial and sensory, the ganglia and
nerves, pigment cells, head connective tissues,
the epidermis, hair, and mammary glands
Mesoderm:layer forms in the embryos of
triploblastic animals. During gastrulation, some
of the cells migrating inward contribute to the
mesoderm, an additional layer between the
endoderm and the ectoderm.
 The formation of a mesoderm led to the
development of a coelom. Organs formed
inside a coelom can freely move, grow, and
develop independently of the body wall while
fluid cushions and protects them from shocks

› Forms the skeletal muscle, the skeleton, the dermis
of skin, connective tissue, the urogenital system, the
heart, blood (lymph cells), and the spleen

Endoderm: is one of the germ layers
formed during animal embryogenesis.
Cells migrating inward along the
archenteron form the inner layer of the
gastrula
› Forms into the stomach, the colon, the liver,
the pancreas, the urinary bladder, the lining of
the urethra, the epithelial parts of trachea, the
lungs, the pharynx, the thyroid, the
parathyroid, and the intestines.