Photosynthesis Key Definitions

Question 1

biomass

Answer 1

the total mass in living organisms, usually shown as the mass after drying

Question 2

cellulose

Answer 2

plant cell walls are made of tough cellulose, which support the cell and allow it to keep its shape

Question 3

chloroplast

Answer 3

a green disc containing chlorophyll, found in plant cells. this is where the plant makes glucose through photosynthesis.

Question 4

endothermic reaction

Answer 4

a type of reaction in which energy from the surroundings is transferred to the products, e.g. photosynthesis

Question 5

food chain

Answer 5

a diagram that use arrows to show the flow of energy through organisms that depend on each other for food.

Question 6

gas exchange

Answer 6

a process in which one gas diffuses across a membrane and another gas diffuses in the opposite direction.

Question 7

glucose

Answer 7

the sugar produced by photosynthesis and needed for respiration

Question 8

guard cell

Answer 8

the sugar produced by photosynthesis and needed for respiration

Question 9

lipid

Answer 9

a substance in a large group of compounds that includes fats and oils

Question 10

palisade cell

Answer 10

tall, column-shaped cell near the upper surface of a plant leaf

Question 11

photosynthesis

Answer 11

A series of enzyme-catalysed reactions carried out in the green parts of plants. Carbon dioxide and water combine to form glucose. This process requires energy transferred by light.

Question 12

polymer

Answer 12

A long-chain molecule made by joining many smaller molecules (monomers) together.

Question 13

producer

Answer 13

An organism such as a plant that makes its own food using photosynthesis.

Question 14

protein

Answer 14

a polymer made up of amino acids

Question 15

protist

Answer 15

An organism that belongs to a kingdom of eukaryotic and mainly single-celled organisms (also called a protoctist).

Question 16

respiration

Answer 16

A series of reactions occurring in all living cells, in which glucose is broken down to release energy.

Question 17

starch

Answer 17

A polymer carbohydrate that is made by the joining together of glucose molecules.

Question 18

stomata

Answer 18

A tiny pore in the lower surface of a leaf, which, when open, allows gases to diffuse into and out of the leaf. Plural is stomata.

Question 19

storage organ

Answer 19

A plant organ used to store energy-rich substances such as starch – for example, a potato.

Question 20

sucrose

Answer 20

The type of sugar found in the phloem of plants and used as table sugar.

Question 21

concentration

Answer 21

The amount of something found in a certain volume of another substance. For example, the amount of a solute dissolved in a certain volume of solvent.

Question 22

direct proportion

Answer 22

A linear relationship in which the percentage change in a variable occurs with an equal percentage change in another variable. A direct proportion is seen as a straight line through the origin when the two variables are plotted on a graph.

Question 23

inverse proportion

Answer 23

A non-linear relationship where one variable decreases in size at the same rate as another increases.

Question 24

inverse square war

Answer 24

A mathematical relationship in which a quantity varies in inverse proportion to the square of the distance from the source of the quantity.

Question 25

limiting factor

Answer 25

A single factor that, when in short supply, can limit the rate of a process such as photosynthesis.

Question 26

linear relationship

Answer 26

A relationship between two variables (quantities) shown by a straight line on a graph.

Question 27

rate

Answer 27

how quickly something happens

Question 28

active transport

Answer 28

The movement of particles across a cell membrane from a region of lower concentration to a region of higher concentration (against the concentration gradient). This process requires energy.

Question 29

concentration gradient

Answer 29

the difference between two concentration

Question 30

diffusion

Answer 30

The random movement and spreading of particles. There is a net (overall) diffusion of particles from regions of higher concentration to regions of lower concentration.

Question 31

fluid

Answer 31

a liquid or gas

Question 32

mineral ion

Answer 32

ion from a naturally occurring salt

Question 33

nitrate

Answer 33

A compound that contains nitrogen in the form of a nitrate ion.

Question 34

osmosis

Answer 34

The overall movement of solvent molecules in a solution across a partially permeable membrane, from a dilute solution to a more concentrated one.

Question 35

partially permeable membrane

Answer 35

Describes a membrane that will allow certain particles to pass through it but not others. Another term for semi-permeable membrane.

Question 36

root hair cell

Answer 36

A cell found on the surface of plant roots that has a large surface area to absorb water and dissolved mineral salts quickly from the soil.

Question 37

wilt

Answer 37

drooping of parts of a plant caused by lack of water

Question 38

companion cell

Answer 38

A specialised cell located in the phloem tissue of plants. They pump sucrose into sieve cells.

Question 39

lignin

Answer 39

A type of polymer that is combined with cellulose in some plant cell walls to make the cells woody, e.g. in xylem cells.

Question 40

phloem tissue

Answer 40

Living tissue formed of sieve tubes and companion cells that transports sugars and other soluble compounds around a plant.

Question 41

potometre

Answer 41

A device used for measuring the rate of water uptake by a plant.

Question 42

sieve tube/ cell

Answer 42

Tubes formed of phloem sieve cells (so called because the cells have holes in their ends). The tubes carry sugars and other soluble compounds around the plant.

Question 43

translocation

Answer 43

The transport of sugars (mainly sucrose) and other soluble compounds in the phloem tissue of a plant.

Question 44

transpiration

Answer 44

The flow of water into a root, up the stem and out of the leaves.

Question 45

xylem vessel/ cell

Answer 45

A long, thick-walled tube found in plants, formed from many dead xylem cells. The vessels carry water and dissolved mineral salts through the plant.