Ch. 6 - Chromosomes and Cell Divison

Question 0

Why are offspring genetically different from their parents?

Answer 0

1. The alleles come from 2 parents.
2. Crossing over.
3. Reassortment of homologues.

Question 1

Define nondisjunction.

Answer 1

The unequal distribution of chromosomes during meiosis due to the centromeres.

Question 2

What are the products of mitosis & meiosis?

Answer 2

Mitosis: 2 diploids (identical)
Meiosis: 4 haploids (unique)

Question 3

What is the difference between Anaphase 1 & 2?

Answer 3

In anaphase 2, the sister chromatids are pulled apart and separated by spindle fibers instead of the 2 being pulled apart together.

Question 4

Explain the steps in Prophase 1?

Answer 4

1. Replicated chromosome condense.
2. Spindle is formed
3. Homologous pairs of sister chromatids come together and cross over.
4. Nuclear membrane disintegrates.

Question 5

Define crossing over.

Answer 5

When the maternal and parental chromosomes change parts.

Question 6

What separates during meiosis 1 & 2?

Answer 6

Meiosis 1 separates homologous chromosomes. Meiosis 2 separates sister chromatids.

Question 7

During meiosis, how many daughter cells are created? How about mitosis!

Answer 7

4; 2

Question 8

What is a sister chromatid?

Answer 8

One of the two identical copies of a chromosome created during replication, held together by a centromere.

Question 9

What are homologous?

Answer 9

Maternal and paternal copies of chromosome.

Question 10

What are two important features about meiosis?

Answer 10

1) reduces the amount of genetic material in gametes.

2) all gametes are different.

Question 11

Define gametes.

Answer 11

Sex cell.

Question 12

What is meiosis?

Answer 12

The generation of sperm and egg. A process that enables organisms to make special reproductive cells.

Question 13

Define a diploid.

Answer 13

Has 2 copies of each chromosome.

Question 14

Define a haploid.

Answer 14

A cell that has 1 copy of each chromosome.

Question 15

What is a somatic cell?

Answer 15

An asexual cell (every cell in our body).

Question 16

Why does cancer live forever? Why do they spread so much?

Answer 16

The telomeres rebuild. They don’t stick together which causes them to run throughout the body.

Question 17

What is a tumor?

Answer 17

Unregulated cell division. They ignore the signals that the area is full so they keep producing and pilling up on top of each other.

Question 18

What is the cause of cancer?

Answer 18

A cell that was supposed to die but didn’t, and kept growing, dividing, leading to unrestrained cell growth.

Question 19

What happens during Anaphase?

Answer 19

The chromatids split and each part is pulled away by a spindle fiber.

Question 20

What happens during Metaphase?

Answer 20

The chromosomes all meet in a center line called the equator.

Question 21

What happens during Telophase?

Answer 21

Two cells begin to form from the one cell.

Question 22

What is Cytokinesis?

Answer 22

The end result of mitosis (2 daughter cells).

Question 23

What are the steps of mitosis?

Answer 23

1) prophase
2) metaphase
3) anaphase
4) telophase

Question 24

What is apoptosis?

Answer 24

Pre-planned process of cell suicide. (End of a cells life)

Question 25

What are the 3 reasons for mitosis?

Answer 25

1) growth
2) repair
3) replacement

Question 26

What is the purpose of mitosis?

Answer 26

To enable existing cells to generate new, genetically identical cells.

Question 27

How do genetic mutations occur.

Answer 27

An error can occur during replication.

Question 28

What happens during replication?

Answer 28

It unwinds, pairs (rebuild) and gets shipped off.

Question 29

What happens in all the Interphase phases?

Answer 29

Gap 1: primary growth
Syntheses: preparations for division
Gap 2: 2nd growth period

Question 30

How do prokaryotes divide or reproduce?

Answer 30

Binary fusion, or asexually (duplicate then divide)

Question 31

What are telomeres?

Answer 31

A protective cap at the end of DNA.

Question 32

How does a telomere disappear? What happens when all the telomeres are gone?

Answer 32

Every time a cell divides, the telomere looses a little bit. Once the telomere is gone, the DNA starts getting eaten away causing cancer, diseases, ect.