Bio Chap.4

Question 1

What is the Cell Theory?

Answer 1

• All living things are composed of one or more cells.
• Cells are the smallest units of living organisms.
• New cells come only from pre-existing cells by cell division.

Question 2

“Traits are passed on through _____ in the form of DNA”

Answer 2

genetic material

Question 3

DNA stands for?

Answer 3

Deoxyribonucleic acid

Question 4

What does the nucleus do in a cell?

Answer 4

The nucleus is the control centre of the cell and tells the cell what to do

Question 5

What are chromosomes made up of?

Answer 5

Chromosomes are made up of DNA

Question 6

What is inside the nucleus?

Answer 6

Inside the nucleus are some thread-like structures called Chromosomes.

Question 7

What is DNA?

Answer 7

DNA is a chemical that contains the instructions that mean the cell can make a copy of itself.

Question 8

What are sections of DNA called?

Answer 8

Genes

Question 9

What are genes responsible for?

Answer 9

Genes are responsible for an organism’s features.

Question 10

What are some examples of genes?

Answer 10

Ex; Eye colour, hair colour, skin colour, and height

Question 11

What are the three functions of cell division in multicellular organisms?

Answer 11

Growth of the organism, repair of tissues and organs, and maintenance to replace dead cells

Question 12

Somatic cell =?

Answer 12

Body cell (not including reproductive cells (gametes))

Question 13

As one cell completes a cycle…

Answer 13

it becomes two cells

Question 14

How long does the cell cycle last in most healthy, actively dividing animal cells?

Answer 14

12 to 24 hours

Question 15

What are the 3 main stages in the cell cycle?

Answer 15

1. Interphase: growth and intense cell activity
2. Mitosis: The cell’s nucleus and genetic material divide
3. Cytokinesis: division of the cell cytoplasm and creation of new cells.

Question 16

Interphase is divided into what 3 phases?

Answer 16

Growth 1(G1), Synthesis (S), and Growth 2 (G2).

Question 17

What is G1

Answer 17

G1 is the major period of growth.

Question 18

What happens in the S phase?

Answer 18

S phase is when DNA (also called chromatin) is replicated.

Question 19

What is G2?

Answer 19

G2 involves further growth and molecule synthesis.

Question 20

What happens when DNA is replicated during Interphase?

Answer 20

The double helix unwinds and each strand of DNA serves as a template for a new strand. Each new double helix contains one original strand and one new strand.

Question 21

What are the structures involved in Mitosis?

Answer 21

• Chromosomes
• Sister chromatid
• Centromere
• Spindle Fibre
• Centrosome

Question 22

What is a chromosome?

Answer 22

A structure in the nucleus that contains DNA.

Question 23

What is sister chromatid?

Answer 23

One of two genetically identical chromosomes and are held together at the centromere.

Question 24

What is a centromere:

Answer 24

The region where two sister chromatids are held together in a chromosome.

Question 25

What is spindle fibre?

Answer 25

A microtubule structure that facilitates the movement of chromosomes within a cell.

Question 26

What is a centrosome?

Answer 26

A structure that helps to form the spindle fibres.

Question 27

True or False: Is the process of cytokinesis different in different cell types?

Answer 27

True

Question 28

How do animal cells divide during cytokinesis?

Answer 28

In animal cells, an indentation forms in the cell membrane along the cell's equator. It deepens as the cytoplasm divides equally, and the cell pinches off into two cells.

Question 29

How do plant cells divide during cytokinesis?

Answer 29

In plant cells, the rigid cell wall does not pinch inward. Instead, a new structure called a cell plate forms between the daughter nuclei. A cell wall forms on each side of the cell plate

Question 30

What is DNA comprised of?

Answer 30

Nucleotides

Question 31

What are Nucleotides made up of?

Answer 31

Sugar (deoxyribose), A phospahte group, and a base.

Question 32

What are the 4 bases?

Answer 32

-Adenine (A) -Guanine (G) -Cytosine (C) -Thymine (T)

Question 33

Across the middle of the helix, what pair with what?

Answer 33

Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

Question 34

How is DNA shaped?

Answer 34

DNA is shaped like a long, spiralling double helix

Question 35

How many chromosomes do humans have?

Answer 35

46

Question 36

How many pairs of chromosomes do humans have?

Answer 36

23

Question 37

1 of the 23 pairs of chromosomes are special, what are they?

Answer 37

Sex chromosomes

Question 38

What are sex chromosomes?

Answer 38

An X or Y chromosome, which determines the genetic sex of an organism.

Question 39

True or False: The two chromosomes, called X and Y are homologous.

Answer 39

False

Question 40

XX = ?, XY = ?

Answer 40

Female, Male

Question 41

What are the rest of the chromosomes called?

Answer 41

Autosomes