Transcript BIOLOGY - San Marcos Unified School District

BIOLOGY
Final Exam Review
Scientific Method
• Organized technique of solving problems or
answering questions about the world around us.
• It’s Role in Science
– Gives focus and direction to investigations
• Steps
1)
2)
3)
4)
5)
State the Problem (Question)
Gather Information and Form a Hypothesis
Experiment to Test the Hypothesis
Record and Analyze Data
Draw Conclusions
Hypothesis vs Theory
Hypothesis
Theory
A proposed solution or
answer to a scientific
question/problem.
A well tested explanation
that is well supported .
An idea to be tested!
Must be testable!
Already has been tested
many times!
Explains a wide range of
observations from various
experiments
Experimentation
Experiments need to be controlled whenever possible!
Controlled experiment means only
1 factor (variable) is being altered between the control
and experimental groups
Control Group
Experimental Group
-same conditions as
experimental group except factor
being tested (manipulated
variable)
-All other factors (variables) are
kept constant (= constants)
-used for comparison
-Manipulated variable is
deliberately altered.
*ex: cholesterol drug
-Responding variables are
monitored to see if there is any
difference from control group
*ex: cholesterol levels
decrease more than
subjects in control group
Sources of Error During Experimentation
Avoidable
Unavoidable
• Can be prevented
• Can’t be prevented.
– An experimental error- a
mistake was made during
experiment.
– Small group sizes
• Less reliable results
– Variation (differences) in test
subjects that couldn’t be
detected before experiment.
Models in Science
• Can be used to help us understand key and
complex concepts
• help explain information (data) and make
predictions
• Models have limitations
• Can not always show all details or complexities of a paticular
concept
Tools in Our Biology Classroom
• Microscope
– Enables us to view things that cannot be seen with
the naked eye
– Cells
Cumulative Nature of Science
Science IS NOT History
• Scientific ideas and theories can be altered and or thrown
out if new evidence comes about
• Scientists publish their work so:
– Other scientists can experiment and test their ideas
– Their work can continue after they’ve finished
– Others can apply their work to more advanced work
• Know how Rosalind Franklin’s work contributed to Watson
and Crick’s discovery of the structure of DNA!
Macromolecules
Organic Compounds
Substance
Monomer
Polymer
Protein
Amino Acids
Polypeptide
(Protein)
Carbohydrates
Monosaccharides
(Simple Sugars)
Polysaccharides
(Starches)
Nucleic Acids
Nucleotides
DNA and RNA
Lipids
Fatty Acids & Glycerol
Lipid
(Fats, Oils, & Waxes)
Cell Membrane
Function: A thin flexible barrier that separates the cell from its surroundings
Fluid Mosaic Model
-Mainly made of LIPIDS (bilayer) & PROTEINS
Movement of Molecules Through The Membrane
Passive- n o energy required
*substances from high to low concentration
ex: diffusion, osmosis
Active- energy required
* substances move from low to high concentration
ex: protein pumps, endocytosis, exocytosis
Protein Production
• Genes (DNA) in the nucleus contain coded instructions to
make each type of protein the body needs
• mRNA takes a “copy” of these coded instructions from the
DNA in the nucleus to the ribosomes in the cytoplasm
(usually attached to rough Endoplasmic Reticulum)
• Ribosomes use instructions and link together amino acids
together to form proteins (polypeptides)
DNA  mRNA  protein (amino acid sequence)
transcription
translation
Role of:
Endoplasmic Reticulum and Golgi Apparatus
Production and Release (Secretion) of Proteins
• Endoplasmic Reticulum
• Has RIBOSOMES attached to it (gives rough appearance)
• Provides a site for ribosomes to do work!
– Protein production (synthesis)
• Golgi Apparatus
• PACKAGES PROTEINS (inside vesicles) so they can be shipped out of
the cell!
ER  Golgi  Vesicles to Cell Membrane
Enzymes & Chemical Reactions
Enzymes are special proteins produced within our
cells
Enzymes are biological catalysts that speed up
chemical reactions
– Lower the activation energy needed to get reactions started
Lock and Key Theory- Enzymes help substrates
(reactants) fit together in the correct fashion so
bonds holding reactants together can be broken
more easily
– Atoms can then rearrange themselves to form products
Structure (Shape) & Function of Enzymes
– Enzymes rely on their structure (shape)to work properly
– Altering pH, temperature, or ionic conditions may alter structure
(shape of the enzyme)
• Enzymes no longer work 
Cell Types
• Prokaryotic
• Small
• No Nucleus
• Simple
• Plant (Eukaryotic)
• Rectangular
• Cell Wall- rigid outer
coating made of cellulose
• Chloroplast- site of
photosynthesis
• Eukaryotic
• Larger
• Nucleus
• Complex- many organelles
• Animal (Eukaryotic)
• Oval or Irregular
• No Cell Wall
• No chloroplasts
Cell Processes
Photosynthesis
• Occurs in Chloroplast
CO2 + H2O  C6H12O6 + O2
Light Dependent
Occurss in Thylakoid Membranes
Light Independent- Calvin Cycle
Occurs in Stroma
Chlorophyll Capturees Energy From Sunlight
to Power the Reaction
ATP and NADPH Power the Reaction
Reactant- H2O (Water) Product O2 (Oxygen)
Reactant- CO2 Product- C6H12O6
Carbon dioxide
Glucose
Also
ADP + P  ATP
NADP+  NADPH
Also
ATP  ADP + P
NADPH  NADP+
Cellular Processes
Cellular Respiration
• Occurs in Mitochondria
• Also called Aerobic Respiration because oxygen is required
C6H12O6 + O2  CO2 + H2O + Energy
• Energy Released is Used to Replenish the Cell’s supply of ATP
• Stages
Glycolysis  Kreb’s Cycle  Electron Transport Chain
Cell Specialization
• Multicellular Organisms- cells have specialized
tasks
– Example: White Blood Cells Fight Disease, Red Blood Cells
Carry Oxygen
– ALL cells have SAME DNA
– Specific cells produce only the proteins they need
to do their job within the body
• Cells only express (transcribe and translate) the genes
for proteins they need to do their tasks.
» Example: Red Blood Cells make the protein to carry
hemoglobin. No other cells in our body make
hemoglobin.
DNA
Deoxyribonucleic Acid
GENETIC CODE OF LIFE
• Made of Nucleotides
– Nucleotide- sugar, phosphate, nitrogen
• Nucleotides link together to form
double helix or “twisted” ladder
• Sides of the ladder are made of
alternating deoxyribos (sugar)
and phospate groups
• Rungs of the ladder are made two
Nitrogen bases bonded together
Adenine (A) always Thymine (T)
Guanine (G) always bonds with Cytosine (C)
DNA & Chromosome Structure
• DNA Coils and Condenses to form
chromosomes
• Humans have 46 chromosomes
• 23 Homologous (Matching)Pairs
• We pass on 1 of each type of chromosome to our offspring
during reproduction
DNA Replication
process in which DNA copies itself
• Semiconservative
– Each new molecule has
• 1 Original Strand
• 1 Newly Formed
“Complementary” Strand
• Follows Rules of Base Pairing
– A bonds with T
– G bonds with C
RNA vs DNA
• RNA is single stranded instead
of double stranded
• RNA has base uracil (U)
instead of Thymine (T)
• RNA has sugar ribose instead
of deoxyribose
Protein Synthesis
making proteins inside the cell
• DNA is the code for producing proteins within our
cells
• Be able to transcribe DNA gene into mRNA and
translate mRNA into the amino acid sequence of
a protein
TAC CCG GCC
??? ??? ???
??? ??? ???
DNA gene
mRNA sequence?
Amino acid sequence of protein?
(abreviate)
Meiosis
• Meiosis ONLY occurs in the reproductive organs of the body
(Ovaries of Females, Testes of Males)
• Meiosis creates GAMETES or REPRODUCTIVE CELLS (Egg or Ova for
Females and Sperm for Males)
• Gametes are Haploid (N) which means they half the number of chromosomes
as our somatic (regular body) cells which are diploid (2N)
Crossing Over During Meiosis
• Matching “homologous” chromosomes can
exchange genes during Prophase I of Meiosis
• This adds genetic variety to offspring
DNA &Fertilization
Fusion of Sperm and Egg Ova
• Sperm and Egg Cell’s Are Haploid (N)-23 chromosomes
23 + 23 = 46
(N)
(N)
(2N)
• Chromosomes combine to form Diploid (2N) zygote
(fertilized egg)- 46 chromosomes total
– 23 chromosomes from each parent
– Offspring inherit half their DNA
Genotype vs Phenotype
Genotype- Genetic make-up of an organism or type of
genes (alleles) they have for a particular trait
allele- different forms of a gene
Phenotype- The expression or appearance for the trait
Genotype
FF
Ff
ff
Phenotype
Free (detached) earlobes
Free (detached) earlobes
attached earlobes
Mendel’s Law of Dominance
B = Brown allele
B = Blue allele
HOMOZYGOUS- Having two of the SAME alleles or genes for trait.
- also referred to as being purebred for the trait
BB- homozygous dominant
bb- homozygous recessive
HETEROZYGOUS- Have two DIFFERENT alleles or genes for a trait
- also referred to as being hybrid for the trait
Bb- heterozygous
• LAW of DOMINANCE- Some alleles are “stronger” than others and will
mask the “recessive” allele when in the heterozygous individual
EXAMPLE
Bb = Brown eyes
Mendel’s Law of Segregation
• Alleles separate or segregate during the
formation of gametes (meiosis)
– You pass on only 1 allele (gene) for each trait
– Not both
Bb  B or b
meiosis
Punnett Squares
• Can be used to predict possible genotypes and
phenotypes for offspring
• Also allow us to predict probabilities
F = free ealobes f = attached earlobes
1) Two people are heterozygous (Ff), what are the
possible genotypes and phenotypes for offspring?
What is the chance for free ealobes? What is the
chance for attached earlobes?
2) One person is heterozygous (Ff) and other parent
has attached earlobes…?
3) One person is homozygous with free ealobes and
other parent is heterozygous…?
Mendel’s Law of Independent
Assortment
• The Genes or Alleles You Pass On For One Trait Does
Influence the Genes or Alleles You Pass On For a Different
Trait
• What allele combinations could be found in the
reproductive cells of the following examples?
H= horned
h = no horns
1)hhLL
2)Hhll
3)HhLl
L = long hair
l = short hair
Sex Determination
Males-XY
Females- XX
• Parents contribute 1 sex chromosome each
• Female EGGS will always contain an X chromosome
• Male SPERM CELLS may contain the X chromosome or
the Y chromosome (50/50 chance)
• So Males Determine the Sex of Offspring