Cell Division, Diversity and Organisation - Differentiation

Question 1

define differentiation

Answer 1

cells can become specialised to perform a particular function

Question 2

what is the role of erythrocytes

Answer 2

transport oxygen and CO2

Question 3

how can cells differentiate

Answer 3

several ways - the shape or contents can vary, including having different numbers of organelles

Question 4

where are erythrocytes produced

Answer 4

bone marrow

Question 5

what do erythrocytes lose during differentiation

Answer 5

nucleus, mitochondria, golgi apparatus, rough ER

Question 6

what do erythrocytes contain

Answer 6

haemoglobin

Question 7

how are erythrocytes specialised for their function

Answer 7

• biconcave disc (large surface area aids gas exchange by diffusion)
• no nucleus, making room for haemoglobin
• very small, allowing it to travel through tiny capillaries and so get very close to cells in body tissues

Question 8

what is the function of neutrophils

Answer 8

engulf microbes (phagocytosis)

Question 9

where are neutrophils produced

Answer 9

bone marrow

Question 10

what do neutrophils contain

Answer 10

• lots of lysosomes
• multilobed nucleus

Question 11

where are neutrophils found

Answer 11

normally found in bloodstream but can squeeze out of capillaries to fight infection

Question 12

how are neutrophils specialised for their function

Answer 12

• multilobed nucleus
• granular cytoplasm - some are lysosomes which contain enzymes for digesting bacteria, others are glycogen granules

Question 13

where are squamous epithelial cells found

Answer 13

surfaces:
- lining of blood vessels (gives low friction surface for fluids)
- alveoli (gives short diffusion distance for gases)

Question 14

how are squamous epithelial cells specialised for their function

Answer 14

• thin, flat cells (short diffusion distance)
• basement membrane

Question 15

what is a basement membrane

Answer 15

• made of collagen and glycoproteins
• secreted by the cells
• attaches cells to tissues

Question 16

where are ciliated epithelial cells found

Answer 16

• trachea
• bronchi
• bronchioles
• oviducts

Question 17

how are ciliated epithelial cells specialised for their function

Answer 17

• column shaped cells
• possess cilia which waft mucus or ovum
• many mitochondria
• basement membrane

Question 18

how are sperm cells specialised for their function

Answer 18

• small, long, thin shape
• undulipodium (contains microtubules for movement)
• nucleus contains 1 set of chromosomes (haploid)
• mitochondria (aerobic respiration releases energy to swim)
• acrosome containing digestive enzymes (specialised lysosome to digest outside of egg)

Question 19

how are palisade cells specialised for their function

Answer 19

• long, thin cells with thin cellulose cell walls (light only has to pass through epidermis and one cell wall)
• contains lots of chloroplasts for photosynthesis
• chloroplast can be moved by cytoskeleton

Question 20

where are root hair cells found

Answer 20

near tips of roots

Question 21

how are root hair cells specialised for their function

Answer 21

• thin cell wall
• hair like projection (increases surface area)
• aids absorption of water and minerals
• relatively large numbers of mitochondria for uptake of mineral ions by active transport

Question 22

how are guard cells specialised for their function

Answer 22

• only epidermal cells with chloroplasts
• hoops of cellulose microfibrils prevent cells getting wider when they swell
• in daylight when stomata opens so CO2 can enter leaf:
  chloroplasts make sugars
  guard cells actively pump in K+ ions (lowers water potential inside cell)
• thicker inner walls stretch less so cells curve