AP Biology Exam Notes Review

Flashcards for AP Biology Unit 6, 7, and 8 Exam Review

DNA Structure

Made of nucleotides with a five-carbon sugar (deoxyribose), phosphate, and nitrogenous bases (Adenine, Guanine, Cytosine, Thymine).

Base Pairing in DNA

A with T (2 hydrogen bonds), C with G (3 hydrogen bonds). Strands are antiparallel (5' to 3').

Genome

A species' complete DNA; segments are chromosomes.

Chromosomes and Histones

DNA associates with histones forming nucleosomes; euchromatin is active, heterochromatin is inactive.

DNA Replication

Semiconservative process forming two DNA molecules from one (each new DNA = 1 old + 1 new strand). Helicase unwinds DNA. Synthesis starts from RNA primers. Leading strand is continuous; lagging strand consists of Okazaki fragments linked by DNA ligase.

Central Dogma

Transcription (DNA →RNA) and translation (RNA → protein). mRNA is the template for protein synthesis.

Types of RNA

mRNA (messenger), tRNA (transfer amino acids), rRNA (part of ribosome).

Gene Expression Regulation

Regulated at transcription via transcription factors and post-transcription via RNAi. Operons in prokaryotes control multiple genes.

Mutations and Biotechnology

Base substitutions. Recombinant DNA merges DNA from different sources. PCR amplifies DNA, and gel electrophoresis separates fragments. Transduction enables gene transfer via viruses.

Endotherms

Animals that generate their own body heat through metabolism.

Ectotherms

Animals rely on heat from their environment.

Instinct

Behaviors animals are born with.

Learning

Changes based on experiences and interactions with the environment.

Imprinting

Young animals attach to the first moving object they see.

Habituation

Animals stop reacting to familiar stimuli.

Circadian Rhythms

Internal clocks regulate daily behaviors.

Pheromones

Chemical signals for mating or marking territory.

Agonistic Behavior

Aggression and threats during conflicts.

Territoriality

Defending specific areas for resources.

Altruistic Behavior

Helping others at a personal cost to support the group.

Mutualism

Both species benefit.

Commensalism

One species benefits, the other is unaffected.

Parasitism

One species benefits at the other's expense.

Photoperiodism

Flowering based on light exposure.

Tropisms

Growth responses to environmental cues.

Phototropism

Growing toward light for better photosynthesis.

Gravitropism

Roots grow down due to gravity, stems grow up.

Thigmotropism

Growth in response to touch.

Ecosystem

Interactions between living things and their physical surroundings.

Community

Different populations in an area interacting.

Population

A group of the same species in a specific area.

Gross Productivity

Total energy from photosynthesis.

Net Productivity

Energy remaining after accounting for respiratory losses.

Keystone Species

Crucial for ecosystem balance.

Evolution

How populations change over time, mainly through natural selection.

Darwin's Ideas

Species make more babies than can survive, creating competition for resources. Differences among individuals help some survive longer and reproduce better.

Lamarck's Theory

Traits gained during a lifetime could be passed to offspring.

Fossils

Dating fossils by looking at the rocks they're found in; shows change over time.

Biogeography

Finding similar species in different places that are far apart - clues to ancestry.

Embryology

Young stages of vertebrates show similar features, like gill slits - shared ancestor.

Body Structure

Animals with similar body parts suggest they have a common ancestor.

Genetics - Evidence of Evolution

DNA similarities provide strong proof of evolution; all life shares a genetic code.

Genetic Variability

Differences in traits among individuals are necessary for natural selection to happen. More variation = better survival.

Peppered Moths

Moths changed color because of changes in the environment, affecting which color variant survived better.

Genetic Drift

Random changes in how common certain traits are.

Gene Flow

Movement of genes between populations.

Sexual Selection

Preferences for certain traits can affect which individuals get to reproduce.

Speciation

New species can form when populations are isolated from each other.

Hardy-Weinberg Principle

Allele frequencies don't change if conditions are stable. Changes in these frequencies can indicate evolution.

Origins of Life

Early Earth had no oxygen; it was filled with gases like methane and ammonia. The RNA-world hypothesis suggests that RNA was one of the first forms of life.