Fundamentals of Genetics and Inheritance

Fill-in-the-blank flashcards covering basic genetics, chromosome structure, meiosis, sex determination, and inheritance patterns.

The basic unit of heredity is the .

gene

Genes are segments of DNA that code for .

traits

Traits an organism displays are known as .

phenotypes

Variations of genes are called .

alleles

Most human cells contain ____ chromosomes, found in 23 pairs.

46

Approximately ____ genes code for proteins that perform most life functions.

22,000

A pair of homologous chromosomes consists of one chromosome from the maternal and one from the paternal parent; these are called chromosomes.

homologous

At each genetic locus, an individual has two , one on each homologous chromosome.

alleles

The location of a gene on a chromosome is its .

locus

A heterozygous genotype example is .

Cc

In meiosis, crossing over occurs in the stage of Prophase I.

pachytene

The site where crossing over occurs between two chromosomes is called a .

chiasma

Meiosis I results in ____ haploid cells from a single diploid cell.

two

Meiosis II results in a total of ____ haploid cells.

four

The XIST gene is expressed to inactivate one X chromosome, forming a Barr .

body

Barr bodies are the X chromosomes in female somatic cells.

inactive

The SRY gene initiates development of .

testes

In X-Y systems, males are and females are .

heterogametic; homogametic

In haplodiploid systems, males are and females are .

haploid; diploid

X-chromosome dosage compensation in mammals is achieved by the process of one X chromosome becoming .

inactivated

XCI phases include nucleation, spreading, and .

maintenance

Quantitative traits are typically continuous and are influenced by multiple genes, also called .

polygenic

Heritability is the proportion of phenotypic variance due to genetic factors; a value of 1 indicates the trait is entirely due to .

genetic factors

X-linked genes are located on the chromosome.

X

A karyotype is a representation of an individual's complete set of chromosomes.

photographic

The connection holding the sister chromatids together is broken during .

anaphase

The organizing center of microtubules in animal cells is called the , also known as the MTOC.

centrosome

The paired structure of homologous chromosomes in prophase I is called a .

bivalent