Meiosis and Chromosomes

A set of flashcards based on lecture notes about meiosis, chromosome types, and related genetic disorders.

What are the two types of cells that organisms that reproduce sexually are made up of?

Somatic cells and Gametes.

What do somatic cells contain in terms of chromosome number?

They contain the diploid number (2n).

What are gametes?

Gametes are sex cells that contain half the normal number of chromosomes, known as haploid number (n).

What is the male gamete called?

Sperm.

What is the female gamete called?

Ovum (plural: ova).

What is fertilization?

The fusion of a sperm and egg to form a zygote.

What chromosome number does a zygote have?

A zygote has a diploid number of 46 chromosomes (2n=46).

What are homologous chromosomes?

A pair of chromosomes that are similar in shape and size and carry genes controlling the same inherited traits.

How many pairs of homologous chromosomes do humans have?

Humans have 23 pairs of homologous chromosomes.

What are autosomes?

Chromosomes that code for most of the offspring's traits, which are sets 1 - 22 in humans.

What are sex chromosomes?

Chromosomes that determine the sex of the offspring, which are the 23rd set in humans.

What happens if meiosis does not occur?

The chromosome number in each new generation would double, leading to issues in offspring viability.

What is spermatogenesis?

Meiosis in males that produces sperm.

What is oogenesis?

Meiosis in females that produces ova.

What occurs during Prophase I of meiosis?

Homologous chromosomes condense and synapsis occurs, forming tetrads.

What is crossing over?

A process during Prophase I where segments of nonsister chromatids break and reattach, creating genetic variation.

What is independent assortment?

The random orientation of homologous pairs during Metaphase I, contributing to genetic variation.

What is non-disjunction?

The failure of homologous chromosomes or sister chromatids to separate during meiosis.

What is Down's Syndrome?

A genetic disorder caused by the presence of an extra copy of chromosome 21 (Trisomy 21).

What is Turner’s Syndrome?

A condition where a female has partly or completely missing an X chromosome (Monosomy 23).

What is Kleinfelter’s Syndrome?

A condition in males characterized by the presence of more than one X chromosome (Trisomy 23, XXY).

What is Amniocentesis?

A procedure used to detect genetic disorders, such as non-disjunction, during pregnancy.

What does a karyotype show?

A picture of an individual's chromosomes used to analyze genetic disorders.

What genetic disorder does Trisomy 21 correspond to?

Down's Syndrome.