Cell biology 2 (B1)

Question 1

cell

Answer 1

smallest structural and functional unit of an organism

Question 2

nucleus

Answer 2

a structure that contains genetic material and controls the acuity of the celll

Question 3

chromosome

Answer 3

a thread like structure of coiled DNA found in the nucleus of a eukaryotic cell

Question 4

DNA

Answer 4

a polymer made up of two strands forming a double helix

Question 5

gene

Answer 5

a section of DNA that codes for a specific protein or characteristic

Question 6

stage one cell Division

Answer 6

growth

increase number of sub-cellular structures e.g ribosomes and mitochondria

Question 7

stage 2 of cell division

Answer 7

DNA synthesis

DNA replicates to form two copies of each chromosomes

Question 8

stage 3 of cell division

Answer 8

Mitosis

• one set of chromosomes is pulled to each end of the cell and the nucleus divides.
• then the cytoplasm and cell membranes divide to form two cells that are identical to the parent cell

Question 9

when does mitosis occur

Answer 9

during growth, repair, replacement of cells

Question 10

when does asexual reproduction occur

Answer 10

by mitosis in both plants and simple animals

Question 11

how are the small intestines adapted for diffusion

Answer 11

villi- increase surface area, good blood supply to maintain concentration gradient , thin membrane- short diffusion distance

Question 12

how are the lungs adapted for diffusion

Answer 12

Alveoli- increase surface area, good blood supply to maintain concentration gradient , thin membrane- short diffusion distance

Question 13

how are the gills in fish adapted for diffusion

Answer 13

Gill filaments and lamella - increase surface area, good blood supply to maintain concentration gradient , thin membrane- short diffusion distance

Question 14

how are the roots adapted for diffusion

Answer 14

root hair cells - large surface area

Question 15

how are the leaves adapted for diffusion

Answer 15

large surface area, thin leaves for short diffusion path, stomata on the lower surface to let oxygen and carbon dioxide in and out

Question 16

Diffusion

Answer 16

movement of particles in a solution from a higher concentration to a lower concentration

Question 17

does diffusion require energy

Answer 17

NO

Question 18

Osmosis

Answer 18

movement of water molecules from a dilute solution to a more concentrated solution through a partially permeable membrane
e.g plants absorbing water from soil

Question 19

Active transport

Answer 19

movement of water molecules from a dilute solution to a more concentrated solution
e.g movement of mineral ions into roots

Question 20

does osmosis require energy

Answer 20

no

Question 21

does active transport require energy

Answer 21

yes

Question 22

adaptions for diffusion

Answer 22

the greater the difference in concentrations the faster the rate of diffusion

Question 23

human embryonic stem cells

Answer 23

can be cloned and made to differentiate into most cells types

Question 24

adult bone marrow stem cell

Answer 24

can form many types of human cells e.g blood cells

Question 25

meristems

Answer 25

can differentiate into any plant cell type throughout the life of the plant