W1 Cells & DNA

Question 1

Describe the cell components of a eukaryotic cell
(Protists,fungi,animals,plants)
(10)

Answer 1

1.cell membrane= controls in & out

2.nucleus=DNA as chromos, controls cellular activities

3.nucleolus=rRNA & proteins for ribos

4.rough ER=ribos, protein synth/mod

5.smooth ER=lipid synth, detoxification, Ca storage

6.Ribos= protein molec synthesized from AA

7.lysosome=has acidic fluid to break bacteria

8.mitochondria=source of chem energy, synths ATP

9.Golgi app=modifies/sorts/packages proteins & lipids from ER, prepares for transport

10.cytoplasm=jelly like, medium for cellular processes

Question 2

Describe prophase (4)

Answer 2

• Chro condense + visible
• Spindle fibers emerge from centrosomes
• Nuclear envelope
breaks down
• Centrosomes move toward
opposite poles

Question 3

Describe prometaphase (3)

Answer 3

• Chromosomes continue to condense
• Kinetochores appear at centromeres
• Mitotic spindle microtubules attach to
kinetochores

Question 4

Describe metaphase (2)

Answer 4

• Chromosomes are lined up at the metaphase
plate

• Each sister chromatid is attached to a spindle fiber originating from
opposite poles

Question 5

Describe anaphase (3)

Answer 5

• Centromeres
split in two

• Sister chromatids (now called
chromosomes) are pulled toward opposite poles

• Certain spindle fibers begin to
elongate the cell

Question 6

Describe telophase (4)

Answer 6

• Chromosomes arrive at opposite poles and begin
to decondense

• Nuclear envelope material surrounds each set of chromosomes

• The mitotic spindle breaks down

• Spindle fibers continue to push poles apart

Question 7

Describe cytokinesis (2)

Answer 7

• Animal cells: a cleavage furrow separates the
daughter cells

• Plant cells: a cell plate, the precursor to a new cell wall, separates the
daughter cells

Question 8

What are the checkpoints of cell cycle?

Answer 8

*interphase,mitosis

*after G1
*after G2
Check for damaged or unduplicated DNA

*metaphase= check for chrom attachment to mitotic spindle

Question 9

Describe meiosis (6)

Answer 9

*interphase
*chromatids pair up as HC
*meiosis 1
*meiosis 2
*4 daughter cells produced
* each with half the number of chromosomes of the parent cell

Question 10

Describe structure of chromosomes (4)

Answer 10

*have a telomere at the top and bottom to help chromo stay together

*kinetochore, helps genome go from mothers cell to daughters cell

*centromere, holds 2 sister chromatids together

Spindle microtubules

Question 11

Describe structure of nucleotide

Answer 11

*5 C sugar
*phosphate group
*nitrogenous base
E.g adenine,cytosine,thymine,
guanine
*deoxyribose in DNA

Question 12

What is a karyotype?

Answer 12

Karyotype is an individuals complete set of chromosomes

Used to check for abnormalities in chromosome number or structure.

important in the study of the human evolution and to understand some pathologies.

Question 13

Describe process of fertilisation

Answer 13

Fertilisation happens when a sperm cell (spermatozoon) successfully meets an egg cell (ova) in the fallopian tube.

Question 14

Outline stages of embryogenesis

Answer 14

Embryonic period: first 10 weeks of development

Fetal period: weeks 11-40

Question 15

What contains nervous tissue

Answer 15

Brain
Spinal cord
Nerves

Question 16

What contains epithelial tissue

Answer 16

Lining of Gl tract organs
and other hollow organs

Skin surface (epidermis)

Question 17

What contains muscle tissue

Answer 17

Cardiac muscle
Smooth muscle
Skeletal muscle

Question 18

What contains connective tissue

Answer 18

Fat and other soft
padding tissue
Bone
Tendon

Question 19

Describe structure of virus

Answer 19

1. Acellular
2. Can’t reproduce on own
3. viral genome (DNA or RNA) encapsulated by proteins
4. Envelop

5.Envelope protein

6. Capsid
7. Enzyme