Genetics and Cell Division Flashcards

Practice flashcards covering key definitions and concepts in genetics, reproduction, inheritance, and cell division.

What is the definition of offspring?

The product of reproduction; a new organism produced by one or more parents.

What is a gene?

A short length of DNA that carries the genetic code for a particular trait/characteristic or cell activity.

How is a trait defined?

A genetically determined characteristic.

What is variation, and what forms can it take?

Differences between organisms within a population, which can be continuous or discontinuous.

What is a gamete?

Reproductive cells that contain half the number of chromosomes compared to the parent cell.

What is sexual reproduction?

Reproduction involving two parents, resulting in offspring different to the parent and to each other.

What are sex chromosomes?

Chromosomes X and Y that determine the sex of an individual.

What are proteins?

Molecules made up of amino acids that exist in many types and all have important roles in living systems.

What does pure breeding mean?

Individuals that are homozygous and will always produce the same offspring when crossed together.

What is a test cross?

A cross between an organism of unknown genotype and a homozygous recessive organism to work out the genotype from the offspring.

What is asexual reproduction?

Reproduction involving only one parent (usually female), producing offspring genetically identical to the parent and to each other.

What is a karyotype?

A photograph of an individual's chromosomes cut out and arranged according to their size.

What is fertilisation?

The joining of male and female gamete.

What does haploid mean?

Having a single set of chromosomes ($n$).

What is a dominant allele?

An allele which is always expressed even if only one is present; written with an upper-case letter (e.g., 'A').

What happens during semi-conservative replication?

In each new DNA double helix, one strand is from the original molecule, and one strand is new.

What does diploid mean?

Having a full set of chromosomes ($2n$); having a pair of each type of chromosome.

What is a heterozygous individual?

An individual with two alleles that are different for a particular trait, or an individual that carries a gene for a particular recessive trait, does not express the trait, but can pass that trait.

What are amino acids?

The basic building blocks of proteins.

What is a clone?

An organism produced asexually from one parent, resulting in offspring genetically identical to both its parent and siblings.

What is a zygote?

A fertilised ovum/egg that contains the full set of chromosomes.

What is the nucleus?

The cell part that contains chromosomes.

What is the double helix structure of DNA?

Two strands of nucleotides wound around each other.

What is a recessive allele?

An allele which is only expressed when two of them are present; written with a lower-case letter (e.g., 'a').

What is meiosis?

Cell division in testes and ovaries producing $4$ new cells (gametes) that are genetically different to each other and to the parent cell.

What are homologous chromosomes?

Chromosomes having the same structural features (length) and pattern of genes.

What is mitosis?

Cell division in body cells for growth and repair that produces $2$ new cells genetically identical to each other and to the parent cell.

What is deoxyribonucleic acid (DNA)?

The substance carrying an organism's genetic information.

What is crossing over?

The exchange of genetic material between homologous chromosomes.

What is independent assortment?

The process where homologous chromosome pairs line up and are sorted separately into sex cells during meiosis, creating genetic diversity in offspring through random mixing.