Genetics and Evolution Lecture Review

These flashcards cover essential concepts in genetics and evolution, including definitions, processes, and the relationships among different biological components.

What is a gene?

A segment of DNA that codes for a particular protein.

What is a locus?

A specific location on a chromosome where a gene is found.

What are homologous chromosomes?

Each member of a pair of chromosomes from each parent that contain the same genes.

What does homozygous mean?

Having two identical alleles at a locus.

What does heterozygous mean?

Having two different alleles at a locus.

What is a true-breeding individual?

An individual that is homozygous for a specific gene.

What is a hybrid?

An individual that is heterozygous for a specific gene.

What is a Punnett Square?

A method to set up potential genetic crosses to predict offspring genotypes.

What is a test cross?

A cross used to determine an unknown genotype by crossing with a homozygous recessive individual.

What does F1 generation refer to?

The first set of offspring from the parental generation.

Define complete dominance.

One allele is completely dominant over another allele.

Define incomplete dominance.

The heterozygous condition results in an intermediate phenotype.

Define co-dominance.

Two dominant alleles are expressed simultaneously in the phenotype.

Which gamete determines the sex of the baby in humans?

The sperm determines the sex due to its X and Y chromosome composition.

What are the blood donation abilities of blood type A?

Can receive from A and O, can donate to A and AB.

What is an environmental influence on gene expression?

Siamese cats have pale fur due to temperature affecting color gene expression.

Are sex-linked diseases more common in males or females? Why?

More common in males because they have only one X chromosome.

What is nondisjunction?

The failure of chromosomes to separate during meiosis.

What evidence suggests DNA is the genetic material?

The amount of DNA doubles prior to cell division.

What are Chargaff's rules?

The amount of Guanine equals Cytosine and the amount of Thymine equals Adenine.

Who performed the X-ray crystallography that led to the DNA structure discovery?

Rosalind Franklin.

What does 'antiparallel' mean in DNA structure?

The two strands of DNA run in opposite directions.

What percentage of human DNA is considered 'junk' DNA?

98.5% of our DNA is junk.

What does DNA helicase do during replication?

Unwinds the double-stranded DNA.

What is meant by semiconservative replication?

Each new DNA molecule consists of one old strand and one new strand.

What is transcription?

The process of creating mRNA from a DNA template.

What is translation?

The process of converting mRNA into a protein.

What are the key differences between DNA and RNA?

DNA is double-stranded; RNA is single-stranded and contains uracil instead of thymine.

What is a codon?

A sequence of three nucleotides in mRNA that codes for an amino acid.

What occurs during termination in transcription?

The RNA polymerase reaches a termination signal and releases the completed mRNA.

What are point mutations?

Mutations that involve a change in a single nucleotide.

Define homologous structures.

Structures that are similar in shape among different species, indicating a common ancestor.

What is artificial selection?

The intentional breeding of organisms to produce desired traits.

What did Charles Darwin propose in his theory of evolution?

Species change over time through natural selection.

What is the relationship between fossil age and depth in geology?

Older fossils are found deeper, while younger fossils are near the surface.