ap biology final

Rosalind Franklin

Used X-ray diffraction to discover the double-helical structure of DNA.

pedigree patterns of inheritance

a family tree indicating the presence or absence of the trait in question for each member of each generation

Mitochrondrial DNA

inherited from mother

Nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Mendel's Law of Segregation

Alleles segregate from one another during the formation of gametes. (anaphase I)

Mendel's Law of Independent Assortment

genes found on different chromosomes are sorted into sex cells independently of one another. (metaphase I)

sex-linked traits

A trait associated with a gene that is carried only by the male or female parent.

Plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

Topiosomerase

relieves overwinding strain ahead of replication forks by breaking, swiveling, and rejoining DNA strands

DNA helicase

An enzyme that unwinds the DNA double helix during DNA replication

single stranded binding proteins

Proteins that act as scaffolding, holding two DNA strands apart during replication

DNA primase

synthesizes a short RNA primer to provide a 3'-OH group for the attachment of DNA nucleotides

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

DNA ligase

A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain.

Transcription

Transcription happens in three main stages:

Initiation: Transcription factors (proteins) help RNA polymerase bind to a specific DNA sequence called the promoter (often rich in T and A bases, known as the TATA box), which acts as the "start here" signal.

Elongation: RNA polymerase unwinds the DNA and reads the template strand in the (3' 5') direction. It builds the new mRNA strand in the (5' 3') direction by adding complementary RNA nucleotides (A pairs with U, C pairs with G).

Termination: The RNA polymerase reaches a specific sequence called the terminator, which causes the enzyme to detach and release the newly formed pre-mRNA transcript.

Translation

Initiation: The small ribosomal subunit binds to the mRNA and the initiator tRNA (carrying the amino acid Methionine, which corresponds to the "start" codon, AUG). The large ribosomal subunit then joins to complete the translation complex. [1

Elongation: The ribosome moves along the mRNA in the 5' to 3' direction. Transfer RNAs (tRNAs) sequentially enter the ribosome, match their anticodons to the mRNA codons, and transfer their amino acids to the growing polypeptide chain.

Termination: The process halts when the ribosome reaches a "stop" codon (e.g., UAA, UAG, UGA). A protein called a release factor binds to the stop codon, detaching the polypeptide chain from the ribosome

Epigenetics

the study of environmental influences on gene expression that occur without a DNA change

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

Mutualism

A relationship between two species in which both species benefit

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Symbiosis

A close relationship between two species that benefits at least one of the species.

Electrophoresis

Charge: DNA has a negatively charged sugar-phosphate backbone. When an electrical current is applied, the DNA migrates away from the negative electrode (cathode) and toward the positive electrode (anode).

Size: The gel acts as a molecular sieve. Shorter DNA fragments easily navigate the pores and travel further down the gel, while longer fragments are slowed down and remain closer to the starting wells

bacterial transformation

ability of bacteria to alter their genetic makeup by uptaking foreign DNA from another bacterial cell and incorporating it into their own

PCR

(polymerase chain reaction) multiple copies of a specific segment of DNA (amplify)

DNA sequencing

Determining the exact order of the base pairs in a segment of DNA.

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

convergent vs divergent evolution

Convergent evolution- process by which unrelated organisms independently evolve similarities when adapting from similar environments

Divergent evolution- the process in which an interbreeding population or species diverges into two or more descendant species, resulting in once similar or related species to become more and more dissimilar

Bottleneck vs Founder Effect

Bottleneck effect; the change in the gene pool of a species by the breeding of a small portion of the alleles of the genes of the parental population. i.e the many of the cheetah's died out, and only a small portion of the population carrying a small portion of the alleles originally present in the population, survived to breed.

Founder effect; a few individuals carrying a small portion of the populations gene pool become isolated from the population and interbreed.

comparison; in the founder effect a small number of individuals from the population relocate to a separate area. Which can be a bottleneck.

Hardy-Weinberg equilibrium

The Hardy-Weinberg equilibrium is a mathematical model used in AP Biology as a null hypothesis to determine if a population is evolving. It states that allele and genotype frequencies will remain constant across generations if five conditions are met: no natural selection, no mutations, no gene flow, large population size, and random mating

Cladogram

A diagram that is based on patterns of shared, derived traits and that shows the evolutionary relationships between groups of organisms

punctuated equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

Gradualism

A proposed explanation in evolutionary biology stating that new species arise from the result of slight modifications (mutations and resulting phenotypic changes) over many generations.

altruistic behavior

action in which an organism helps another at its own expense

Ectotherm

An animal whose body does not produce much internal heat

Endotherm

An organism that is internally warmed by a heat-generating metabolic process

keystone species

A species that influences the survival of many other species in an ecosystem

sexual variation in meiosis

genetic variation in meiosis is driven by three core mechanisms that ensure offspring are genetically unique: crossing over, independent assortment, and random fertilization. These processes shuffle alleles, generating the raw material for natural selection

hydrogen bonding

the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule

Hydrolysis

A chemical process that splits a molecule by adding water.

dehydration reaction

A chemical reaction in which molecules combine by removing water

primary protein structure

sequence of amino acids

secondary protein structure

coiling or folding of a polypeptide due to H-bonding between amino acids (alpha helix and beta plated sheets)

tertiary protein structure

three-dimensional folding pattern of a protein due to side chain interactions

quaternary protein structure

2+ protein chains forming functional protein

structure of amino acids

- An R group

- the amine group

- the carboxyl group

- a hydrogen atom

DNA replication 5'-> 3'

DNA polymerase can only build new DNA strands in the 5' to 3' direction. Because DNA strands are antiparallel (run in opposite directions), this directional constraint creates two different pathways: the continuously built leading strand and the fragment-based lagging strand

Carbohydrates

Carbon, Hydrogen, Oxygen (CHO)

Lipids

(CHOP)

Proteins

(CHONS)

Nucleic Acids

CHONP

Phospholipid Bilayer

Plasma membrane layers composed of phospholipid molecules arranged with polar heads (hydrophilic) facing the outside and nonpolar tails facing the inside. (hydrophobic)

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

Lysosome

cell organelle filled with enzymes needed to break down certain materials in the cell

Mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

Chloroplast

organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy

Vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

Membrane Selective Permeability

Membrane selective permeability is the plasma membrane's ability to regulate which substances enter and exit a cell, maintaining internal homeostasis. This property arises directly from the fluid mosaic structure of the phospholipid bilayer

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

passive transport

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

Exocytosis

Process by which a cell releases large amounts of material

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

water potiential

Water potential is the potential energy of water per unit volume compared to pure water. It measures the tendency of water to move from one area to another through osmosis. Water always flows from an area of high water potential to low water potential

SA:V ratio

The "best" surface area-to-volume (SA:V) ratio is the highest ratio possible. A higher ratio means a cell or organism has more membrane surface area per unit of volume, allowing for highly efficient diffusion of nutrients, waste, and thermal energy

cellular respiration lab setup

The AP Biology Cellular Respiration Lab (often Investigation 6) measures respiration rates by tracking O@ consumption in germinating and non-germinating seeds at various temperatures. Potassium Hydroxide (KOH) is used to absorb CO2 allowing direct measurement of gas volume changes in respirometers

enzyme-substrate complex

A temporary complex formed when an enzyme binds to its substrate molecule(s).

Enzyme reaction rates are affected by

1. Shape- "Lock and Key Model" if it is the wrong shape it will not work.

2. Temperature- each enzyme works best at a specific temperature

3. Ph-- each enzyme works best at a specific ph

What are the steps of cellular respiration?

1. Glycolysis, 2. Pyruvate Oxidation, 3. The Krebs Cycle, 4. Oxidative Phosphorylation

Where does glycolysis occur?

Cytosol/cytoplasm

What happens during glycolysis?

A 6-carbon glucose molecule is split into two 3-carbon pyruvate molecules.

What is the net gain of ATP from glycolysis?

2 ATP

What is produced during glycolysis besides ATP?

2 NADH

Does glycolysis require oxygen?

No, it occurs under both aerobic and anaerobic conditions.

Where does pyruvate oxidation occur?

Mitochondrial matrix

What happens during pyruvate oxidation?

Pyruvate is converted into Acetyl-CoA, releasing CO2 and generating NADH.

Where does the Krebs Cycle occur?

Mitochondrial matrix

What is produced in one turn of the Krebs Cycle?

1 ATP, 3 NADH, and 1 FADH2

What happens during the Krebs Cycle?

Acetyl-CoA combines with a 4-carbon molecule to form citrate and is fully oxidized, releasing CO2.

Where does oxidative phosphorylation occur?

Cristae

What are the two parts of oxidative phosphorylation?

Electron Transport Chain (ETC) and Chemiosmosis

What happens in the Electron Transport Chain?

NADH and FADH2 drop off electrons, creating a proton gradient.

What is the role of oxygen in oxidative phosphorylation?

Oxygen serves as the terminal electron acceptor, forming water.

What powers ATP production during chemiosmosis?

Protons rushing back down their concentration gradient through ATP synthase.

oxidation v reduction

OIL(loss of electrons) RIG (gain of electrons)

- combustion, photosynthesis, metabolism

signal transduction pathway

A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response.

cell cycle stage

1. Interphase

The cell spends about 90% of its life here, preparing to divide. : The cell grows, produces proteins, and carries out its normal metabolic functions.

S Phase (Synthesis): The cell replicates its DNA so each chromosome consists of two identical sister chromatids.

G2 Phase (Gap 2): The cell continues to grow, makes necessary proteins, and duplicates organelles to prepare for the final split.

2. Mitotic (M) Phase

Mitosis and Meiosis Differences

Mitosis: "identical"- one diploid cell(2n) becomes two diploid cells(2n)

Meiosis: "reductional"- one diploid cell(2n) becomes four haploid cells(n)

Cyclins and CDKs

Cyclins and Cyclin-dependent kinases (CDKs) are internal control proteins that regulate the cell cycle. CDKs are enzymes that are always present in the cell but are inactive by default, whereas cyclin levels fluctuate predictably. When cyclins bind to CDKs, they activate a phosphorylation cascade that drives the cell forward into the next phase