Honors Bio Exam Flashcards (all)

genetics, dna replication & translation/transcription, microevolution, macroevolution, applied evolution, and ecology

Blending Hypothesis

An outdated theory suggesting that offspring are a "blend" of the traits of their parents.

Particulate Hypothesis

Mendel’s theory that genes are inherited as discrete units (alleles) that do not blend.

Traits

Characteristics that are inherited, such as eye color or height.

Genetics

The study of heredity and the variation of inherited characteristics.

Purebred (True Breeding)

Organisms that produce offspring identical to the parent in a particular trait.

Cross

Mating of two organisms to observe inheritance patterns.

Cross Fertilization (Cross Pollination)

Fertilization between two different plants with different genetic traits.

Self-Fertilization (Self-Pollination)

When a plant fertilizes itself, typically with its own pollen.

Locus

The specific physical location of a gene on a chromosome.

Gene

A segment of DNA that encodes for a specific protein or trait.

Allele

Different forms of a gene, represented in genotype as letters.

Homozygous

An organism that has two identical alleles for a particular trait.

Heterozygous

An organism that has two different alleles for a particular trait.

Genome

The complete set of genes in an organism.

Genotype

The genetic makeup of an organism, specifically the alleles inherited.

Phenotype

The physical expression or appearance of a trait.

Dominant

An allele that expresses its effect even with one copy present in the genotype.

Recessive

An allele that expresses its effect only when two copies are present.

Punnett Square

A diagram used to predict the genetic outcomes of a cross.

Monohybrid Cross

A genetic cross involving one trait.

Testcross

A cross between an organism with an unknown genotype and a homozygous recessive individual.

Dihybrid Cross

A cross involving two traits.

Probability

The likelihood of a particular genetic outcome occurring.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis.

Random Fertilization

The random combination of gametes during fertilization.

Independent Assortment

The principle that genes for different traits are inherited independently.

Genetic Linkage

Genes close together on the same chromosome are more likely to be inherited together.

Law of Segregation

Mendel's law stating that alleles separate during gamete formation.

Carrier

An individual who carries one copy of a recessive allele but does not express the disorder.

Sex-Linked Genes

Genes located on sex chromosomes, often expressed differently in males and females.

Autosomes

Chromosomes that are not sex chromosomes.

Sex Chromosomes

Chromosomes that determine the sex of an individual.

Incomplete Dominance

A form of inheritance where the heterozygous phenotype is a blend of the two homozygous phenotypes.

Codominance

A form of inheritance where both alleles are equally expressed in the heterozygous phenotype.

Polygenic Traits

Traits influenced by multiple genes, resulting in a continuous range of phenotypes.

Linkage Maps

Diagrams showing the relative positions of genes on a chromosome.

Pedigree

A family tree diagram used to track inheritance patterns of traits.

Karyotype

A photographic representation of an individual's chromosomes.

P, F1, & F2

Generations in Mendel's experiments: P (original) F1 (first offspring) F2 (second offspring).

Gregor Mendel

Father of genetics, conducted experiments with pea plants and formulated the Laws of Inheritance.

Thomas Hunt Morgan

Pioneering geneticist who discovered sex-linked inheritance and genetic linkage.

Reginald C. Punnett

Co-developed the Punnett square for predicting genetic outcomes.

Mendel’s Pea Plant Experiment

Experiment involving cross breeding pea plants to study inheritance patterns.

Genetic Variation

Variability in the genetic makeup of individuals within a population.

Inheritance Patterns

Different ways traits can be passed from parents to offspring.

Testcross

Used to determine the genotype of an individual with a dominant trait.

Bacteriophage (phage)

A virus that infects bacteria, important in studies of genetic material transmission.

Base pairing rules (complementary pairing)

The principle that adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G) in DNA.

DNA polymerase

Enzyme that adds complementary nucleotides to a growing DNA strand during replication; it also checks for mistakes and corrects them.

Double helix

The twisted ladder structure of DNA, formed by two complementary strands of nucleotides.

Helicase

An enzyme that unwinds the DNA double helix ahead of the replication fork.

Lagging strand

The DNA strand that is replicated in small segments (Okazaki fragments) in the direction opposite to the replication fork.

Leading strand

The DNA strand that is synthesized continuously in the direction of the replication fork.

Nucleotide

The monomer unit of DNA, consisting of a phosphate group, a sugar (deoxyribose), and a nitrogenous base (A, T, C, or G).

Okazaki fragments

Short DNA fragments formed on the lagging strand during DNA replication.

Purine

A type of nitrogenous base that has a two-ring structure, examples include adenine (A) and guanine (G).

Pyrimidine

A type of nitrogenous base with a single ring, examples include cytosine (C) and thymine (T).

Replication

The process by which DNA makes a copy of itself.

Replication origins (bubbles)

Sites where DNA replication begins; the DNA is unwound into a bubble-like structure.

Semiconservative replication

A model of DNA replication where each new DNA molecule consists of one original strand and one newly synthesized strand.

Frederick Griffith

Discovered the process of bacterial transformation using Streptococcus pneumoniae.

Oswald Avery

Showed that DNA is the substance responsible for transformation, not proteins.

Martha Hershey and Alfred Chase

Conducted the famous experiment with bacteriophages to demonstrate that DNA, not protein, is the genetic material.

Rosalind Franklin & Maurice Wilkins

Used X-ray crystallography to capture images of DNA, leading to the understanding of its double helix structure.

James Watson & Francis Crick

Proposed the double-helix model of DNA, integrating Franklin’s X-ray data.

Erwin Chargaff

Discovered that the amount of adenine equals thymine, and the amount of cytosine equals guanine in a DNA molecule (Chargaff’s rules).

Monomer of DNA

A nucleotide, which consists of a phosphate group, a deoxyribose sugar, and a nitrogenous base (A, T, C, or G).

Differences between DNA and RNA

DNA has deoxyribose sugar and thymine (T), RNA has ribose sugar and uracil (U). DNA is double-stranded; RNA is single-stranded.

Protein Synthesis Process

Includes transcription (coping DNA code onto mRNA) and translation (using mRNA to create proteins at the ribosome).

Mutations

Changes in the DNA sequence that can alter the amino acid sequence of proteins.

Silent mutation

No effect on the protein.

Missense mutation

A single amino acid is changed.

Nonsense mutation

The change creates a stop codon, shortening the protein.

Frameshift mutation

Insertion or deletion of nucleotides shifts the reading frame, altering subsequent amino acids.

tRNA

Transfers amino acids to the ribosome based on the mRNA codon sequence.

rRNA

Makes up the structure of the ribosome.

Splicing

The process of removing introns and joining exons in pre-mRNA to form mature mRNA.

Species Are Fixed

The belief that species do not change over time.

Adaptations

Traits that increase an organism's chances of survival and reproduction in a particular environment.

Allele Frequency

The proportion of a particular allele among all allele copies in a population.

Analogous Structures

Structures in different species that perform the same function but do not have a common evolutionary origin.

Artificial Selection

Humans intentionally breed organisms with desirable traits.

Binomial Nomenclature

A system for naming species using two names: the genus and species (specific epithet).

Biogeography

Study of the geographic distribution of species.

Bottleneck Effect

A reduction in genetic diversity due to a drastic decrease in population size.

Catastrophism

The idea that Earth’s history has been shaped by sudden, short-lived, and violent events.

Cladogram

A diagram used to show the relationships among species based on shared traits.

Directional Selection

Natural selection that favors one extreme phenotype over others.

Disruptive Selection

Natural selection that favors both extreme phenotypes and eliminates intermediate phenotypes.

Evolution

A change in the genetic makeup of a population over time.

Fitness

The ability of an organism to survive and reproduce.

Fossils

Remains or traces of ancient organisms preserved in rocks.

Founder Effect

A reduction in genetic variation when a small group of individuals starts a new population.

Gene Flow

The transfer of genetic material between populations through migration or interbreeding.

Gene Pool

all the alleles of every individual in a population

Genetic Drift

A random change in allele frequencies in a small population.

Genus

A classification category that ranks above species and below family.

Hardy-Weinberg Equilibrium

A model used to measure genetic changes in a population over time.

Heritability

The proportion of variation in a trait that can be attributed to genetic differences.

Homologous Structures

Structures that have a common evolutionary origin.