biology old

Question 1

limiting factor

Answer 1

a factor that is in short supply, which stops an activity (such as photosynthesis) happening at a faster rate

Question 2

destarching

Answer 2

leaving a plant in the dark for long enough for it to use up its starch stores

Question 3

control

Answer 3

a standard sample that you use as a comparison, to find the effect of changing a variable

Question 4

nectar

Answer 4

a sweet liquid secreted by many insect-pollinated flowers, to attract their pollinators

Question 5

stomata

Answer 5

openings in the surface of a leaf, most commonly in the lower surface; they are surrounded by pairs of guard cells, which control whether the stomata are open or closed

Question 6

guard cells

Answer 6

a pair of cells that surrounds a stoma and controls its opening; guard cells are the only cells in the epidermis that contain chloroplasts

Question 7

epidermis

Answer 7

the outer layer of tissue on a plant; also the outer layer of an animal’s skin

Question 8

secrete

Answer 8

make a useful substance and then send it out of the cell where it is made, to be used in another part of the body

Question 9

cuticle

Answer 9

a thin layer of wax that covers the upper surface of a leaf

Question 10

palisade mesophyll

Answer 10

the layer of cells immediately beneath the upper epidermis, where most photosynthesis happens

Question 11

spongy mesophyll

Answer 11

the layer of cells immediately beneath the palisade mesophyll, where some photosynthesis happens; this tissue contains a lot of air spaces between the cells

Question 12

vascular bundles

Answer 12

collections of xylem tubes and phloem vessels running side by side, which form the veins in a leaf

Question 13

sucrose

Answer 13

a sugar whose molecules are made of glucose and another similar molecule (fructose)
linked together