Module 9 Chapter 5 Mastering

Like mitosis, meiosis involves duplication of the chromosomes before division starts. However, there are __________ rounds of cell division during meiosis and __________ during mitosis.

2, 1

What is the chromosome abnormality that causes Down syndrome?

A nondisjunction results in a person with an extra copy of chromosome 21

How does cytokinesis occur in a dividing animal cell?

By the formation of a cleavage furrow.

If it were to be stretched out, the DNA in one of your cells would be taller than you. How does such a large quantity of DNA fit within the nucleus of one of your cells?

DNA is associated with proteins that compact the DNA to form a package called chromatin

A breeder wants to set up a program to produce zebrafish with long fins. Having long fins is a dominant trait compared to the short fin wild type. Before she can market her zebrafish, she needs to perform a test cross on the long-finned fish she plans to use as a breeder. How can she tell whether her fish are homozygous or heterozygous for the long-finned trait?

Do several test crosses between the long-finned fish and the short-finned fish; if the offspring are always long finned, the long-finned parent is probably homozygous.

What is Mendel's Law of Independent Assortment?

Independent assortment means that each pair of alleles segregates independently of the other pairs of alleles.

What do we call a genetic cross that follows two separate characters, such as pea seed color and pea seed shape

a dihybrid cross

Most human genes come in alternate versions called

alleles

When are the chromosomes of a cell duplicated?

before a cell divides

If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the allele.

dominant

Imagine that eye color in cats is controlled by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is __________ the allele for orange eyes.

dominant to

The ---- is the genetic makeup of an organism.

genotype

Crossing happens during

meiosis

The physical traits of an organism are called its

phenotypes

If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the allele.

recessive

As mitosis begins, __________ are linked together at the centromere

sister chromatids

A --- is one particular variation of a character.

trait

Drag the terms to their correct locations in this concept map about cell division.

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