Genetics and Evolution Flashcards

Flashcards for Genetics, DNA, and Evolution

What are traits?

Characteristics inherited from parents, such as eye color or height.

What is inheritance?

The process by which traits are passed from parents to offspring through genes.

What are genes?

Segments of DNA that code for specific traits.

What are alleles?

Different forms of a gene, such as dominant and recessive versions.

How do dominant traits express?

Expressed with one or two dominant alleles (T)

How do recessive traits express?

Only expressed with two recessive alleles (tt)

What is a homozygous genotype?

Having two identical alleles for a trait (TT or tt).

What is a heterozygous genotype?

Having two different alleles for a trait (Tt).

What is a phenotype?

The physical expression of a trait (e.g., tall or short).

What is a genotype?

The genetic makeup of an organism (e.g., Tt, TT, or tt).

What is the Law of Segregation?

Alleles separate during gamete formation, so each gamete receives only one allele from each pair.

What is the Law of Independent Assortment?

Genes for different traits assort independently during gamete formation.

What is the Law of Dominance?

Some alleles are dominant and mask the expression of recessive alleles.

What is a Punnett square used for?

To predict the possible genotypes and phenotypes of offspring from a genetic cross.

How is probability used in genetics?

To calculate the likelihood of inheriting a specific trait.

What is a monohybrid cross?

A cross that examines the inheritance of one trait (e.g., Tt x tt).

What is a dihybrid cross?

A cross that examines the inheritance of two traits (e.g., YyRr x YyRr).

What is the genotypic ratio?

The ratio of possible genotypes in offspring (e.g., 1 TT: 2 Tt: 1 tt).

What is the phenotypic ratio?

The ratio of observable traits in offspring (e.g., 3 tall: 1 short).

What is the parental (P) generation?

The original pair of individuals in a genetic cross.

What is the F1 generation?

The first generation of offspring from the P generation.

What is the F2 generation?

The offspring of the F1 generation.

What is gamete formation?

The process by which sperm and egg cells are formed with half the number of chromosomes.

What is fertilization?

The joining of a sperm and egg to form a zygote with a full set of chromosomes.

What is a purebred organism?

An organism that is homozygous for a trait.

What is a hybrid organism?

An organism that is heterozygous for a trait.

What is the difference between genes and DNA?

DNA is the molecule that contains genes; genes are specific sequences that code for proteins.

What are the macromolecules and their monomers?

Proteins (amino acids), Nucleic acids (nucleotides), Carbohydrates (sugars), Lipids (fatty acids and glycerol)

What are the components of a nucleotide?

Phosphate group, sugar (deoxyribose), and nitrogenous base.

What type of bond is in the DNA backbone?

Covalent bonds; between bases – hydrogen bonds.

What is the difference between DNA and RNA bases?

DNA has thymine (T); RNA has uracil (U) instead.

What is Griffith’s experiment?

Discovered transformation; harmless bacteria could become harmful by absorbing genetic material from dead harmful bacteria.

What did Hershey and Chase's experiment confirm?

DNA, not protein, is the genetic material using radioactive viruses.

What is Chargaff’s Rule?

Adenine pairs with thymine; guanine pairs with cytosine (A=T, G≡C).

Who created the double helix model of DNA?

Watson, Crick, and Wilkins

Who used X-ray diffraction to take photos of DNA structure?

Rosalind Franklin

What enzymes are used in DNA replication?

Helicase, DNA polymerase, and ligase

What is the central dogma?

DNA → RNA → Protein; flow of genetic information.

What occurs during transcription?

DNA is copied into mRNA in the nucleus.

What occurs during translation?

mRNA is read by the ribosome to build a protein from amino acids in the cytoplasm.

What is the role of mRNA?

Carries genetic code from DNA to ribosome.

What is the role of tRNA?

Brings amino acids to the ribosome during translation.

Where are proteins made?

In the ribosomes, in the cytoplasm or on rough ER.

What is the genetic code?

The sequence of codons in mRNA that determines the sequence of amino acids.

What is a codon?

A three-base sequence on mRNA that codes for a specific amino acid.

What are mutations?

Changes in DNA sequence; can be caused by errors or environmental factors.

What is CRISPR?

Gene editing technology that allows targeted changes to DNA.

What is genetic engineering?

Direct manipulation of genes for practical purposes.

What is recombinant DNA?

DNA made by combining DNA from two different sources.

What is DNA fingerprinting?

Identifying individuals by unique DNA patterns.

What does gel electrophoresis do?

Separates DNA fragments by size using electricity.

What does gene therapy do?

Inserting healthy genes to treat genetic disorders.

What is a GMO?

Genetically modified organism; has altered DNA for desired traits.

What is evolutionary theory?

The scientific explanation of how species change over time through natural processes.

What is natural selection?

Processes where organisms with favorable traits survive and reproduce more.

What does survival of the fittest mean?

The organisms best suited to their environment survive and reproduce.

Why are heritable traits important?

They allow favorable traits to be passed to future generations.

Why is diversity important?

Increases the chance of survival and adaptation in a changing environment.

What are heritable traits?

Traits encoded in DNA and passed from parent to offspring.

What are adaptations?

Inherited traits that improve survival and reproduction in an environment.

How do organisms change over time?

Through genetic variation and natural selection over generations.

What is the endosymbiotic theory?

Theory that eukaryotic cells evolved from symbiotic relationships between ancient prokaryotes.

Why are the Galapagos Islands important?

Helped Darwin develop his theory of natural selection.

Who's theory was not valid? Why?

Lamarck's; he believed acquired traits could be inherited, which is not supported by modern science.

What are the 4 main principles of natural selection?

Variation, Inheritance, Overproduction, Differential survival

What is MRSA?

A bacterial infection resistant to many antibiotics; a “superbug.”

Why is MRSA dangerous?

It is resistant to treatment and spreads easily.

What do antibiotics treat?

Bacterial infections, not viral ones.

Can viruses be treated with antibiotics?

No; antibiotics do not affect viruses.

What is antibiotic resistance?

When bacteria evolve to survive antibiotics, making infections harder to treat.

What is the effect of pesticides like DDT?

Can harm ecosystems and lead to resistant pest populations.

What is a cladogram?

A diagram showing evolutionary relationships between species.

List the 5 sciences that support evolution?

Embryology, Paleontology, Morphology, Biogeography, Biochemistry

What makes up a population?

A group of the same species in a given area.

What is Hardy-Weinberg equilibrium?

A state where allele frequencies don’t change unless certain factors occur.

List the 5 criteria for Hardy-Weinberg equilibrium?

No mutations, Random mating, No natural selection, Large population, No gene flow

List the 5 mechanisms of change?

Mutation, Gene flow, Genetic drift, Natural selection, Non-random mating