Transcript atoms - HCC Learning Web

Animal Cell
Eukaryote (true – nucleus)
Highly specialized function
Very large in size
Lead multicellular existence
Has a fluid plasma membrane
Has many organelles (explain)
Ribosomes translate protein
Rough ER & Golgi secrete
Lysosomes recycle stuff
Peroxisomes detoxify stuff
Mitochondria make energy
Cellular Respiration
• Glucose is broken down by the process of
glycolysis, transferring some energy to ATP.
• The end-products of glycolysis are then fed
into the Kreb’s cycle and metabolized further,
generating reducing power which is converted
to ATP in the mitochondria.
• Cellular respiration is used by heterotrophs,
who are unable to produce their own food (so
who’s cookin’ supper?).
Plant Cell
Very similar to an Animal Cell
Chloroplasts have chlorophyll
Chlorophyll captures light
Light energy makes sugar
Plants need high cell pressure
Vacuoles very large – hold H2O
Also possess a cell wall
Pressure keeps plant erect
Photosynthesis
• This process is carried out by green plants,
green algae and some bacteria in which
energy from sunlight is trapped by
chlorophyll and used for the synthesis of
glucose
• An organism that is able to produce its own
food is termed an autotroph.
Cell Division and Mitosis in Somatic Cells
Mitosis aids in cell duplication
Replaces body’s somatic cells
Composed: Interphase & Mitosis
Interphase: G1, S and G2 phases
G1 is first gap (prep for S)
S is DNA synthesis
G2 is second gap (prep for M)
Mitosis: Chromosome division
Cytokinesis: Cell division
Mitosis and Cytokinesis
G2 of Interphase
Centrosomes
Chromatin
(with centriole
(duplicated)
pairs)
Nucleolus
Nuclear
envelope
Plasma
membrane
Duplicated
cellular
contents
Prophase
Centrosome
Prometaphase
Centromere
Asters
Chromosome, consisting
of two sister chromatids
Chromosomes
condense
&
Centrosomes
Polarize
Fragments
of nuclear
envelope
Kinetochore
Metaphase
Nonkinetochore
microtubules
Kinetochore
microtubule
Nuclear envelope
fragments apart
&
Centrosomes
are polarized
&
Chromosomes
begin to align
Anaphase
Mitotic
Spindle
Centrosome at
one spindle pole
Mitotic
Spindle
forms
&
Metaphase
Plate
forms
Telophase and Cytokinesis
Cleavage
furrow
Metaphase
plate
Daughter
chromosomes
Sister
Chromosomes
are pulled apart
toward poles
Nucleolus
forming
Nuclear
envelope
forming
Nuclear contents
are separated
&
Cell divides
into 2 cells
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Meiotic Production of Gamete Cells
Sexual reproduction works differently from
mitosis. Sperm and eggs are gametes.
Gametes combine their DNA to form a
fertilized cell called a zygote (becomes fetus).
Meiosis is the process wherein gametes
reduce their DNA content to 1 copy of 23
chromosomes (content is halved to 1n).
Somatic cells have a homologous pair of
chromosomes and are 2n or diploid. Gametes
have 1 set of chromosomes and are 1n or
haploid.
Meiosis I
Prophase I
Metaphase I
Centrosome
(with centriole pair)
Sister
chromatids
Telophase I and
Cytokinesis
Anaphase I
Sister chromatids
remain attached
Centromere
(with kinetochore)
Chiasmata
Spindle
Metaphase
plate
Homologous
chromosomes
separate
Homologous
chromosomes
Fragments
of nuclear
envelope
crossover
Microtubule
attached to
kinetochore
Independent
assortment I
Cleavage
furrow
Meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II and
Cytokinesis
Sister chromatids
separate
Haploid daughter cells
forming
Independent
assortment II
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Human Genetics
Genetics is the study of heredity or how traits
are passed on from parent to offspring.
Phenotypes are the physical expressions of
genetic traits (i.e. hair or eye color).
A genotype is the underlying genetic (DNA)
makeup. Genes (on chromosomes) code for
proteins that determine hereditary traits.
Interactions between the genotype and the
environment affect the phenotype (i.e. suntan).
There are multiple forms of a gene, called
alleles. Alleles are represented using letters.
• Dominant alleles are represented by CAPITAL
letters. Recessive alleles are represented by
lowercase letters. (i.e. R vs. r)
• The genotype consists of alleles inherited from
both parents (somatic cells are diploid or 2n).
• When both parents give the offspring the
same allele, the offspring is homozygous for
that particular trait. If each parent gives the
offspring a different allele for a particular trait,
the offspring is heterozygous for that trait.
• To predict what characteristics will occur in
offspring, a Punnet square can be used.
Earth and Physical Science
Periodic Table
A Taxonomic Organization of Chemical Elements
Period – same # of electron shells
Group – same # of outer shell ‘valence’ electrons
In a natural state, the elements are
mostly solids with 10 gases & 2 liquids!
We will come back to this important stuff in a moment…
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The Sun
The sun is the energy source of our planet.
There are many stars (suns) in the galaxies of
the universe existing many light years away.
Our sun is average in energy output but close
to us, thus we receive a lot of energy from it.
Energy from the sun supports life by the
process of photosynthesis and climate.
The energy we receive is an electromagnetic
spectrum, predominantly consisting of visible,
ultraviolet and ionizing radiation.
Radiation is distinguished by its wavelength.
The Electromagnetic Spectrum
10–5 nm 10–3 nm
103 nm
1 nm
Gamma
X-rays
rays
UV
106 nm
Infrared
1m
(109 nm)
Microwaves
103 m
Radio
waves
Visible light
380
450
500
Shorter wavelength
Higher energy
550
600
650
700
750 nm
Longer wavelength
Lower energy
Kinetic and Potential Energies
• Energy and its ability to do work (work is an
applied change in energy) is quantified in units
called Joules or calories.
• The energy associated with motion is kinetic
and is related as: KE = ½ mv2, where m is
mass and v is velocity.
• The amount of stored energy in an object may
be quantified through a calculation of its
potential energy.
• Potential energy can produce kinetic energy
and can be calculated applying the following
equation: PE = mgh, where m is the mass, g is
gravity and h is the height of the object.
• Thermodynamic law dictates conservation.
Laws of Thermodynamics
• The first law of thermodynamics states the
energy of the universe is constant
– Energy can be transferred and
transformed, but cannot be created or
destroyed (i.e. PE to KE)
• The second law of thermodynamics states
during energy transfer or transformation,
some energy is unusable and is lost
– Every energy transfer or transformation
increases the entropy (disorder) of the
universe (i.e. heat)
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Atomic Properties
Matter takes up space and has a mass (matter).
Substances that cannot be broken into simpler
types of matter are elements or atoms and are
arranged in order in the periodic table.
Atoms are composed of 3 sub-atomic particles.
Positively charged protons define the element and
represent the atomic number. Neutrons are
neutral and nuclear. The atomic mass number is
p+ + no. Isotopes differ in mass (number of no).
Electrons are small, negatively charged particles
in nuclear orbit at various energy levels.
A charged atom (ion) has an imbalance of e- to p+.
Summary: Structure of an Atom
Proton (Atomic number)
Atomic nucleus
Neutron
Atom
2
Electron
He
4
Atomic Number
Atomic Mass
Atomic mass = Number of protons + Number of neutrons
Summary: Concepts of Subatomic Particles
Helium Atom
Nucleus
Protons + charge
determine element
Electrons – charge
form negative cloud
& determine
chemical behavior
Neutrons no charge
determine isotope
2
He
4
Atomic Number
Atomic Mass
Patterns within the Periodic Table
The “Representative Elements” are shown
(metals, metalloids, non-metals, gases)
Electrondistribution
diagram
Group 1A
First
Shell
Hydrogen
1H
Atomic mass
Period
1
Alkali Metals
Second
Shell
Lithium
3Li
Alkali Earth
Metals
Group 2A
Metalloids
Beryllium
4Be
Boron
5B
Group 3A
2
He
4.00
Atomic number
Noble Gas
Group 8A
INERT
Helium
2He
Element symbol
Halogens
Group 7A
Non-Metals
Group 4A
Non-Metals Non-Metals
Group 5A
Group 6A
Carbon
6C
Nitrogen
7N
Oxygen
8O
Fluorine
9F
Neon
10Ne
Silicon
14Si
Phosphorus
15P
Sulfur
16S
Chlorine
17Cl
Argon
18Ar
Period
2
Third
Shell
Sodium Magnesium Aluminum
12Mg
11Na
13Al
Period
3
Across a period: accept e-, smaller atomic radius, more electronegative
Down a group: donate e- larger atomic radius, less electronegative (similar chemistry)
Catalysts
• Catalysts control the rate of reactions in which
atoms react to come to a stable state.
• Reaction rates may be increased by the use
of promoters or reduced by the use of
inhibitors, and depend on the frequency of
contact of reactants with catalysts.
• Catalysts are not consumed in a reaction and
increase reaction rate by lowering the
activation energy, lowering the potential
barrier between products in comparison to
reactants.
A
B
C
D
Transition state
A
B
C
D
EA
Reactants
A
B
∆G < O
C
D
Products
Progress of the reaction
• The general reaction is symbolically represented as
the following four-step process:
• As shown above, catalyst (C) generates product (Z)
from the reactants (X and Y).
• First, the catalyst interacts with X and Y, stabilizing a
transition state.
• Next, the reaction proceeds, producing product.
• Finally, the catalyst is released from the product.
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Enzymes
Enzymes are modified globular proteins which
are water soluble and 3D in shape that act as
biological catalysts for reactions in the body.
Enzyme activity is driven by temperature, pH
(H+ ion conc.) and substrate concentration.
An enzyme attaches to a substrate and quickly
converts it to a product due to the reshaping of
the enzyme active site which lowers the
activation energy of the reaction.
Inhibitors can compete with the substrate by
blocking its active sites, causing reduced activity.
E + S  ES  E + P
Acids and Bases
• The pH scale is used to measure the acidic
strength (H+ ion concentration) of a solution.
• Pure water is recognized as the standard of
neutrality between acids (pH<7) and bases
(pH>7).
Stronger acids have smaller
numerical values on the pH
scale.
Stronger bases have greater
numerical values than
weaker bases on the pH
scale.
• The calculation of pH is
based on the activity of
hydrogen ions (H+) dissolved
in solution.
• The pH range of numbers is
based on a logarithmic scale.
pH = - log [H+]
• If a pH meter is not available,
pH indicators such as litmus
paper will suffice to find an
approximate pH.
Chemical Bonds Between Atoms in Molecules
• Chemical bonding primarily occurs through ionic or
covalent interaction between atoms.
• Ionic bonds are an electrical attraction between a
metallic ion (which tends to be a cation +) and a
nonmetallic ion (which tends to be an anion -).
• Ionic bonds complete one another by the donation
and acceptance of electrons to form stable outer
electron shells, creating the molecule.
• Common table salt (NaCl) forms from the positive
Na+ ion and the negative Cl- ion.
Sodium
Chlorine
Sodium
Chloride
• Covalent bonds involve the sharing of electrons
between two atoms and is greatest between atoms
of complementing electronegativity.
• Valence electrons of both atoms are shared
cooperatively to form a stable outer shell for both.
• Carbon is a unique atom and the basis of life due
to its unique chemical structure (4 valence e-)
facilitating stability and bonding to 4 substituents.
More about Electronegativity and Polarity
• Electronegativity is an atom’s attraction for the
electrons in a covalent bond
F O N Cl Br S C H
Most electronegative
Least electronegative
• The more electronegative an atom, the more
strongly it pulls shared electrons toward itself
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Bonding Character in Molecules
Hydrocarbons are saturated or unsaturated.
Saturated hydrocarbons (alkanes) are the most
elementary, composed of 4 single bonds from
Carbon to Hydrogen.
Saturated hydrocarbons are a fuel source.
Unsaturated hydrocarbons have one or more
double or triple bonds between carbon atoms.
Double bonded species are termed alkenes.
Triple bonded species are termed alkynes.
Each hydrocarbon has a special geometry,
producing isomeric forms (3D) of the molecule,
which is the basis of organic chemistry.
General Formula: CnH2n+2
CnH2n
CnH2n-2
Balancing Chemical Reactions
• Every reaction undergoes a dynamic interplay of
reactants combining to form functional products.
• Reactions must balance according to the number
of atoms in the molecule (atomic number per
mol) and the atomic charge of the molecule.
Reduction-Oxidation and Acid-Base Reactions
• Oxidation involves electron donation
producing a more positively charged ion.
• Reduction involves electron acceptance
producing a more negatively charged ion.
• Redox reactions involve the coupled donation
and acceptance of electrons between species
in a chemical reaction.
• An acid is any compound with a higher
hydrogen ion activity than water. A base is
any compound with a lower hydrogen ion
activity than water.
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Chemical Properties of Water
Water is a molecule of hydrogen and oxygen,
polarizing electron localization and charge,
resulting in stabilization thru covalent bonding.
Pure water is a pH standard (7), central to
acid-base neutrality and enzyme function.
Water density is greatest when cold (freeze)
and lowest when hot (vaporized gas).
Water has a high specific heat and heat of
vaporization, moderating Earth’s climate.
Water is a universal solvent considered
necessary for life in the universe.
–
Hydrogen bond
(1) Facilitates lattice
(2) Absorbs energy
+
H
+
O
–
–

+
H
+
–
Effect of water on climate
Santa Barbara 73°
Los Angeles
(Airport) 75°
70s (°F)
80s
San Bernardino
100°
Riverside 96°
Santa Ana
Palm Springs
84°
106°
Burbank
90°
Pacific Ocean
90s
100s
San Diego 72°
40 miles
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States (Phases) of Atoms or Molecules
Motion is always occurring in chemistry and
can be random or ordered in range.
Atomic order is dependent on temperature
and pressure (PV = nRT) which effects the
state of matter (solid, liquid or gas).
Solids are fixed in shape and volume and can
be crystalline in order. Liquids are fluid and
spread over a shape and have a greater
volume. Gases exhibit a pronounced change
in volume and shape. What is plasma?
Latent heat is related to phase transition.
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Evaporation, Vaporization and Condensation
Phase transition involves heat in a system.
Heat is the flow of energy due to temperature.
Evaporation occurs by physical collisions at
the surface layer of a liquid, thereby removing
faster-moving liquid molecules.
Vaporization occurs through a phase
transition from a liquid to a gas, breaking the
physical bonds within the liquid. (heat into)
Condensation occurs through a phase
transition from gas to a liquid, creating
physical bonds within the gas. (heat out of)