Chromosome Sex Determination and Cell Divison

Define Genome

All the DNA in a cell

What are histones

Postiviley charged proteins that DNA wrap around to form nucleosomes

What do Histones do?

Protects DNA from damage, regulates gene expression, and organizes DNA into structural units

What is Chromatin?

Complex of both DNA and proteins that build chromosomes

What are chromosomes?

Condensed packages of DNA

Define Homologs

The nucleus of some organisms that contain two or more pairs of chromosome types

Define Autosomes

Homologs of nearly identical size and genetic composition

Define Sex Chromosomes

Chromosomes that differ each other in size and composition

n= ?

number of distinct chromosome types

a number before the n indicates the what

number of each chromosome type present

what is the total number of chromosomes and how many of each type is there?

n=6

2n=6

2n=46

1. total number - 6, types- 1

2. 6, 2

3. 46, 2

True or false

Humans have 23 pairs of chromosomes and 46 total

true

Define Polyploid

cells with more than two pairs of every chromosome

true or false

polyploidy is fatal in humans

true

why is polyploidy so rare in animals?

the more complicated developmental processes are, the less common polyploidy is, and mammals have a highly complicated gene regulatory system

why is polyploidy so common in plants?

In animals they have developmental complexity while plants have biochemical complexity, and polyploid disrupts development, but enhances biochemical complexity

every time a cell divides….

1. its DNA is duplicated

2. the DNA is divided evenly between the parent and daughter cell

cells come from other cells by…

divison

what are the two types of cell division

mitosis and meiosis

both mitosis and meiosis are accompanied by

cytokinesis

what is the difference between mitosis and meiosis

meiosis leads the daughter cells having half the amount of genetic material as the parent cell, while mitosis daughter cells have the same amount of genetic material as the parent cells.

What kind of reproduction do single cell and multicellular organisms result in

single - asexual

multicellular- sexual and asexual

in multicellular organisms cell division allows what in organisms

repair