Chapter 12 Review for Genetics

What are body cells? What are they used for in the body?

Somatic cells. They are used to make up tissues and organs

What are germ cells and where are they produced?

They are specialized cells that make gametes. They are produced in reproductive organs

What are gametes?

Sex cells (sperm and egg)

What are the gametes for males and females?

Male: Sperm

Female: Ova (egg)

What is the purpose of gametes?

Reproduction

How many pairs of chromosomes do humans have? How many individual chromosomes?

23 pairs, 46 individual

What is a homologous pair and where do homologous chromosomes come from?

Chromosomes with same genes/traits - half from mom/half from dad

What pairs of chromosomes are the autosomal chromosomes?

First 22

Which pair of chromosomes are the sex chromosomes?

23rd pair

Which sex chromosome is larger and has more genes?

X

What genetic makeup gives you males and females?

XX = Female

XY = Male

What is sexual reproduction? What is fertilization?

Sexual reproduction is the fusion of 2 gametes

Fertilization is the actual fusion of egg and sperm

What does it mean to be diploid and where does each set of chromosomes come from in a diploid cell?

Diploid means there's 2 copies of each chromosome

Half comes from each parent

What is meiosis? What does it produce?

Meiosis is the process that produces gametes (sperm and egg cells) with half the number of chromosomes.

What are sister chromatids attached by?

Centromere

What happens in each stage of meiosis?

Prophase II: Starting cells are the haploid cells made in meiosis I. Chromosomes condense.

Metaphase II: Chromosomes line up at the metaphase plate.

Anaphase II: Sister chromatids separate to opposite ends of the cell.

Telophase II: Newly forming gametes are haploid, and each chromosome now has just one chromatid.

What is crossing over with chromosomes and why is this important?

Exchanging genes to increase genetic diversity

How does mitosis and meiosis differ?

- Mitosis: Growth, repair, asexual, 1 division, 2 cells, body cells, diploid to diploid, no crossing over, identical clone, no pairs, lifelong.

- Meiosis: Sexual reproduction, 2 divisions, 4 cells, Germ cells (Egg and sperm), Diploid to haploid, crossing over, unique variations, homologous pairs, limited time

What is gametogenesis?

Production of gametes

What allows the sperm to move and make it to the egg?

The flagella

What is the main purpose of the sperm in fertilization?

To bring the male's DNA to the egg

How many functional sperm are made during spermatogenesis?

Four functional sperm cells

How do eggs form?

Meiosis I produces 1 cell and one polar body

Meiosis II produces 1 egg and 2 polar bodies

How many functional eggs are made during oogenesis?

One functional egg

What are polar bodies?

The cells formed by meiosis in females that are broken down

What is the difference between identical and fraternal twins in terms of genetics and how they form?

Fraternal: Come from 2 separate eggs and sperm

Identical: Come from 1 egg and 1 sperm

Why is Mendel so important?

He laid the groundworks for genetics

What are traits?

Characteristics that are inherited

What is genetics?

The scientific study of heredity

What do P and F1, F2, etc. stand for?

P = Parental Generation

F1 = Offspring of parents

F2 = Offspring of parents offspring

What traits did Mendel look at? What was so important about picking these traits?

Tall/short, axial/terminal, round/wrinkled, yellow/green - they are either/or traits - no inbetween

Difference between homozygous and heterozygous?

Homozygous = 2 identical alleles

Heterozygous = 2 different alleles

What are genes, locus, allele, and genome?

Gene: Piece of DNA that directs a cell to make certain protein

Locus: Specific position on a pair of homologous chromosomes

Allele: Alternative forms of a gene that may occur at a specific locus

Genome: All of your genetics

What are genotypes, phenotypes, dominant, and recessive?

Genotypes: Genetic makeup of specific genes

Phenotypes: Physical appearance

Dominant: Allele that is expressed

Recessive: Allele that is masked

Difference between monohybrid and dihybrid?

Monohybrid: Only one trait is examined, cross-matching of 2 organisms

Dihybrid: Involves 2 traits

What is cross, testcross, law of independent assortment (LOIA), and probability?

Cross: 2 organisms reproducing for the purpose of studying genetics

Testcross: Cross b/w organism w/ unknown genotype and an organism with recessive phenotype

LOIA: Allele pairs separate independently of each other during meiosis

Probability: Number of ways a specific event can occur, over, number of total possible outcomes

What are 3 ways that meiosis gives genetic variation?

Crossing over, law of independent assortment, random fertilization of gametes

What is genetic linkage?

The principle that genes/alleles that are physically close to each other on a chromosome tend to not get separated in meiosis and recombination. They are typically inherited together.