biology final review. chromosomes chromosomes are dna & its associated proteins. we have 46...
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Biology Final Review
Chromosomes
• Chromosomes are DNA & its associated proteins. We have 46 chromosomes or 23
pairs of chromosomes.
• In a prokaryotic cell, it is the main ring of DNA.
Autosomes vs. Sex Chromosomes
• Autosomes are any chromosomes that are not directly involved in determining the sex of an individual.
We have 22 pairs.
• Sex chromosomes contain genes that will determine the sex of the individual.
We have one pair. Females are XX. Males are XY.
Autosomes vs. Sex Chromosomes
Gametes
• Gametes are an organism’s reproductive cells. Female’s gametes are eggs or ova. Male’s gametes are sperm.
Haploid vs. Diploid
• Haploid refers to a cell (gamete) that contains only 1 set of chromosomes.
It is represented by “n.”
• Diploid refers to a somatic or body cell that contains 2 sets of chromosomes.
It is represented by “2n.”
Define Haploid
• Describes a cell, nucleus or organism that has only one set of unpaired chromosomes.
Define Diploid
• A cell that contains 2 sets of haploid chromosomes
• Body or somatic cells contain a diploid number of chromosomes.
Karyotype
• A picture of the chromosomes found in an individual’s cells at metaphase of mitosis & arranged in homologous pairs & in order of diminishing size with the sex chromosomes last.
• Down’s Syndrome
is trisomy 21.
Parts of a Microscope
Microscopes and Magnification
• Ocular lens x objective lens = total magnification
• Magnification – making image appear larger
• Resolution – clarity of image
Cell Theory
• All living things are made of cells.
• Cells are the basic units of structure and function in organisms.
• All cells come from existing cells.
Prokaryote vs. Eukaryote
• Prokaryote No nucleus No membrane bound organelles Circular DNA Relatively small Reproduce quickly (20 min.)
Examples: Bacteria
Prokaryote vs. Eukaryote
• Eukaryote Nucleus Many membrane bound organelles Linear DNA Relatively large Reproduce slowly (24+ hours)
Examples: Plants, animals, fungi & protists
Cell Parts & Functions
• Cell membrane Controls what enters & leaves a cell;
separates & protects the cell from the environment.
• Nucleus Contains the DNA in eukaryotic cells;
controls cellular activities.
• Vacuole Membrane bound sac that stores water, may
also contain ions, nutrients & waste.
Cell Parts & Functions
• Chloroplast Organelle that uses light energy to make
carbohydrates from CO2 & H2O.
• Cytoplasm Region of the cell within the membrane that
includes the fluid, the cytoskeleton and all of the organelles except the nucleus.
• DNA Material that contains the information that
determines hereditary characteristics.
Cell Parts & Functions
• Ribosomes Organelle composed of RNA & protein; site
of protein synthesis.
• Mitochondrion Cell organelle surrounded by 2 membranes &
is the site of cellular respiration, which produces ATP.
• Cell Wall Rigid structure that surrounds the cell
membrane & provides support to the cell.
5 Stages of the Cell Cycle
5 Stages of the Cell Cycle
• The first 3 stages are collectively called interphase. (90% of a cell’s life is spent here.)
1. First growth (G1) phase Cell grows rapidly & carries out
routine functions. (Major portion of a cell’s life is spent here.)
5 Stages of the Cell Cycle
2. Synthesis (S) phase Cell’s DNA is copied. Each chromosome consists of 2 chromatids
attached at the centromere.
3. Second growth (G2) phase Preparations are made for the nucleus to
divide. Microtubules are rearranged. Organelles are manufactured or reproduced.
5 Stages of the Cell Cycle
4. Mitosis The nucleus of a cell divides into 2
nuclei each with the same # and kinds of chromosomes as the original cell.
5. Cytokinesis The cytoplasm divides and 2 new cells
are formed.
3 Checkpoints
• A checkpoint is an inspection point at which feedback signals from the cell can trigger the next phase of the cell cycle or delay it.
1. Cell Growth (G1) checkpoint at the end
of the G1 phase Makes the decision of whether or not a
cell will divide.
3 Checkpoints
2. DNA synthesis (G2) checkpoint at the
end of the G2 phase DNA replication is checked by DNA
repair enzymes.
3. Mitosis checkpoint at the end of mitosis Triggers the exit from mitosis
4 Phases of Mitosis
1. Prophase Chromosomes become
visible. Nuclear envelope
dissolves. The spindle forms. In animal cells, the
centrioles move to opposite poles and the spindle forms between them.
4 Phases of Mitosis
2. Metaphase Chromosomes
move to the center of the cell & line up along the equator.
Spindle fibers link the chromatids of each chromosome to opposite poles.
4 Phases of Mitosis
3. Anaphase Centromeres divide. The 2 chromatids
(now called chromosomes) move toward opposite poles as the spindle fibers attached to them shorten.
4 Phases of Mitosis
4. Telophase A nuclear envelope
forms around the chromosomes at each pole.
The chromosomes uncoil and return to chromatin form.
The spindle dissolves.
Cytokinesis begins.
Cytokinesis
• Division of the cytoplasm of a cell• Follows the division of the cell’s nucleus by
mitosis or meiosis• Cytokinesis in animal cells occurs when a
belt of protein threads pinches the cell membrane in half.
• Cytokinesis in plant cells occurs when vesicles from the Golgi apparatus fuse to form a cell plate.
Cytokinesis
• Cytokinesis in Cytokinesis in
animal cells plant cells
Define Meiosis• A process in cell division during which the number
of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells (gametes or spores)
What are the 4 things that give rise to variation within a species?
• Independent assortment
• Crossing-over
• Random fertilization
• Mutations
Differentiate between spermatogenesis & oogenesis.
• Spermatogenesis2 nuclear
divisions in which the cytoplasm is divided equally
4 sperm produced from parent cell
Differentiate between spermatogenesis & oogenesis.
• OogenesisFirst nuclear division,
cytoplasm divides unequally – one of the cells gets nearly all of the cytoplasm
This cell will ultimately give rise to one egg – the 3 polar bodies will die
Complete the following diagrams
Process: Mitosis
Process: Meiosis
2n2n
2n
Compare Mitosis and Meiosis
What are the 3 different ways asexual reproduction occurs?• In asexual reproduction, a single parent
passes exact copies of all of its DNA to its offspring.
• Fission
• Fragmentation
• Budding
Nondisjunction
• One or more chromosomes fail to separate properly during meiosis.
• One gamete ends up receiving both chromosomes and the other gamete receives none.
• Trisomy occurs when the gamete w/ both chromosomes fuses w/ a normal gamete, resulting in an offspring w/ 3 copies of a chromosome instead of 2.
Diffusion vs. Osmosis
• Diffusion The movement of particles from regions of
higher concentration to regions of lower concentration.
Ex: perfume spreading across a room.
• Osmosis The diffusion of water from an area of high
concentration to an area of low concentration across a membrane.
Ex: Getting thirstier when you drink salt water.
Passive vs. Active Transport
• Passive Transport Does not require energy. Movement down the concentration
gradient. Examples:
Diffusion Osmosis Facilitated diffusion
Passive vs. Active Transport
• Active Transport Requires energy. Movement against the concentration gradient. Examples:
Sodium-potassium pump Endocytosis
Phagocytosis Pinocytosis
Exocytosis
Fig. 5-1a
Cholesterol
Glycoprotein
Glycolipid
Carbohydrate ofglycoprotein
Phospholipid
Microfilamentsof cytoskeleton
Integrin
ATP
• The energy “currency” of the cell.• An organic molecule that acts as the
main energy source for cell processes• Composed of a nitrogen base, a sugar
& 3 phosphate groups. • The energy is stored in the phosphate
bonds.• Powers metabolism.
Photosynthesis
• Process by which plants, algae & some bacteria use sunlight, CO2 &
H2O to produce carbohydrates & O2.
• Takes place in the chloroplast
• Main pigment is chlorophyll.
• Reactants are CO2 and H2O
• End products are glucose & O2
Photosynthesis
• Stage 1 Consists of the absorption of light
energy which excites the electrons in chlorophyll.
The electrons enter the ETC (electron transport chain).
Water is split to produce O2, H+, and
the electrons to replace those lost by the chlorophyll molecules.
Photosynthesis
• Stage 2 The conversion of light energy into
chemical energy that is temporarily stored in ATP and NADPH.
The energy from ATP and NADPH will be used to power the third stage.
Photosynthesis
• Stage 3 CO2 fixation occurs
Inorganic CO2 is fixed into organic
compounds (sugars).
Cellular Respiration
• Process by which cells produce energy from carbohydrates; O2
combines w/ glucose to form H2O &
CO2.
• Takes place in the mitochondrion.
• Reactants are glucose and oxygen.
• Products are carbon dioxide & water.
Aerobic Respiration vs. Anaerobic Respiration
• Aerobic Respiration Requires oxygen. Produces much more ATP (38 net ATP)
• Anaerobic Respiration Does not require oxygen. Regenerates NAD+ so that gylcolysis can
continue. (2 net ATP from glycolysis)
Aerobic Respiration
• Stage 1 – Glycolysis takes place in the cytoplasm.
Does not require oxygen. Glucose is broken down to 2 pyruvate
molecules Produces 2 net ATP and 2 NADH
• Stage 2 – Bridge reaction carries pyruvates into the mitochondrion.
2 CO2 and 2 NADH are produced
Aerobic Respiration
• Stage 3 – Krebs Cycle occurs in the matrix of the mitochondrion
In the presence of oxygen. In two turns of the Krebs Cycle:
4 CO2 are produced
6 NADH are produced 2 ATP are produced
2 FADH2 are produced.
Aerobic Respiration
• Stage 4 – Electron Transport Chain occurs in the inner membrane of the mitochondrion
In the presence of oxygen. 34 net ATP produced
2NADH from glycolysis = 6ATP 2 NADH from bridge reaction = 6 ATP 6 NADH from Krebs cycle = 18 ATP 2 FADH2 from Krebs cycle = 4ATP
Anaerobic Respiration or Fermentation
• Alcoholic Fermentation Occurs in the absence of oxygen Occurs in yeast and some bacteria Produces:
Ethyl alcohol Carbon dioxide Regenerates NAD+ so glycolysis can
continue
Anaerobic Respiration or Fermentation
• Lactic Acid Fermentation Occurs in the absence of oxygen Occurs in the muscle tissue of animals
& in lactic acid bacteria Produces:
Lactic acid Regenerates NAD+ so glycolysis can
continue
Atom and Its Parts
• An atom is the smallest unit of an element that maintains the properties of that element.
Nucleus contains: Proton (+) Neutron (Neutral)
Electron cloud Electron (–)
Covalent vs. Ionic Bonds
• Covalent Bond Bond formed when atoms share pairs of
electrons.
• Ionic Bond Bond formed by the attraction between
oppositely charged ions.
Covalent vs. Ionic Bonds
Molecules and Polar Molecules
• Molecule A group of atoms held together by
covalent bonds.
• Polar Molecule Shares its electrons unequally and
therefore has partially positive and negative ends, or poles.
Water is a polar molecule.
Molecules and Polar Molecules
Solvents
• Solvent A substance, usually a liquid,
capable of dissolving another substance.
• Universal Solvent Water.
pH Scale and Acids & Bases• pH Scale ranges from 0 - 14
Acid A compound that forms hydrogen ions (H+) in water. Its pH is 0 to less than 7. (0 to < 7)
Base A compound that forms hydroxide ions (OH-) in water. Its pH is greater than 7 to 14. (>7 to 14)
Neutral Substances that have a pH of 7.
Organic Macromolecules
• Organic macromolecules: Contain carbon atoms that are covalently
bonded to other elements – typically hydrogen, oxygen and other carbon atoms.
4 principal classes of organic compounds found in living things are: Carbohydrates Lipids Proteins Nucleic acids
Organic Macromolecules
• Carbohydrates – organic compounds made of carbon, hydrogen and oxygen in a 1:2:1 ratio.
Monomers are monosaccharides. Ex: Glucose and fructose
Polymers are polysaccharides. Ex: Starches, potatoes, paper, crab shells
Functions Stores energy. Makes up cell walls in plants and fungi. Makes up exoskeleton in some animals.
Organic Macromolecules• Lipids are nonpolar molecules that are
insoluble in water & include fats, phospholipids, steroids and waxes.
Monomers are glycerol & fatty acids Polymer examples
Butter & oil All membranes Cholesterol and Steroids
Functions Stores energy Makes up cell membranes Acts as chemical messengers
Organic Macromolecules• Proteins
Monomers are amino acids Polymer examples
Hemoglobin and antibodies Muscle, hair and nails
Functions Hemoglobin carries oxygen and antibodies help
defend against infection. Make up tissues that support body structures and
provide movement Speed up chemical reactions (enzymes)
Organic Macromolecules• Nucleic acids
Monomers are nucleotides Polymer examples
DNA RNA
Functions Controls cellular activities Stores hereditary information Plays key role in the manufacture of
proteins
Catalyst vs. Enzyme
• Catalyst Speeds up chemical reactions by
lowering the activation energy.
• Enzyme Specialized protein that acts as an
organic catalyst.
Test Indicators & Positive Results
• Benedict’s solution Tests for simple sugars – blue color changes
to red, orange, yellow, green.
• Lugol’s iodine Tests for starch – reddish–orange iodine turns
blue-black or black.
• Biuret solution Tests for protein – blue turns purple.
• BTB (Bromthymol blue) Tests for CO2 – blue turns green, or yellow.