cells

Question 1

give 3 differences between prokaryotes and eukaryotes

Answer 1

prokaryotes have no nucleus while eukaryotes have a nucleus
prokaryotes are smaller and simpler cells while eukaryotes are larger and more complex cells
prokaryotes have a unicellular structure while eukaryotes have multicellular, but some are unicellular
prokaryotes cells walls are made of peptidoglycan while some eukaryotes cell walls are made of chitin and cellulose

Question 2

state the parts of a eukaryotic cell

Answer 2

nucleus, cell membrane, mitochondria, cytoplasm, ribosomes, cellulose cell wall, chloroplasts and vacuole

Question 3

what is cell specialization?

Answer 3

a situation whereby cells develop special structures which assist them on carrying out their functions

Question 4

define cell division

Answer 4

a process by which a parent cell separates into 2 daughter cells with identical set of chromosomes

Question 5

what is the function of:
1. cell membrane
2. cytoplasm
3. nucleus
4. mitochondria
5. chloroplasts
6. vacuole?

Answer 5

1. control movement of substances in and out of the cell ( partially/selectively permeable)
2. site for chemical reactions in a cell/ where unaerobic respiration takes place
3. controls all activities taking place in the cell
4. where energy (aerobic respiration) is generated
5. site for photosynthesis
6. stores ions

Question 6

what is the function of the following cells?
1. root hair cell
2. ciliated cell
3. nerve cell
4. erythrocytes (red blood cells)
5. phagocytes
6. lymphocytes
7. sperm
8. muscle
9. guard cell
10. palisade cell

Answer 6

1. absorbs water and mineral salts from the soil
2. sweep and brush mucus containing dust and bacteria up the respiratory tract
3. conduct nerve impulses
4. carry oxygen from lungs to body tissues
5. engulf and digest bacteria
6. produce antibodies which attack antigens
7. fertilizes the ovum and pass on genetic information
8. contract to produce movement
9. regulate transpiration by opening and closing stomata
10. where photosynthesis takes place

Question 7

differentiate between xylem and phloem cells

Answer 7

xylem transport water and mineral salts from roots up the plant while phloem transport amino acids and sugars to growing parts of the plant.

Question 8

what is the use of mitosis?

Answer 8

replaces the dead cells

Question 9

what is the use of meiosis?

Answer 9

produces the sex cells for reproduction

Question 10

what is the importance of cell division?

Answer 10

1. growth & development
2. tissue repair & regeneration
3. reproduction
4. cell replacement

Question 11

stages of cell division in mitosis

Answer 11

prophase, metaphase, anaphase & telophase

Question 12

stages of cell division in meiosis1

Answer 12

prophase 1, metaphase 1, anaphase 1 & telophase1

Question 12

what happens in the prophase stage

Answer 12

• chromosomes shorten and become thick and visible
• centrioles move to the opposite side of the cell
• nuclear membrane disappears

Question 13

ANAPHASE STAGE?

third stage of mitosis

Answer 13

• centromere splits into 2 to form 2 chromatids
  -SF pull the chromatids to opposite sides

Question 13

METAPHASE STAGE?

second stage of mitosis

Answer 13

-chromosomes line up along the metaphase plate of the cell
- formation of spindle fibers
- SF become attached to the chromosome of the centromere

Question 14

TELOPHASE STAGE?

last stage of mitosis

Answer 14

• chromatids reach opposite sides
• SF disappear
• nucleus forms around each set of chromatids
• cytokinesis occurs/ cell separates into 2 daughter cells
• chromatids replicate such that the 2 daughter cells have the same number of chromosomes as the parent cell.