Key concepts - topic 1 (pg 1-12) paper 1 & 2

Question 1

cell membrane

Answer 1

controls what enters and leaves the cell e.g. oxygen

Question 2

nucleus

Answer 2

large structure that contains genes (DNA) that control the cell

Question 3

cytoplasm

Answer 3

jelly substance that fills the cell - reactions take place here

Question 4

mitochondria

Answer 4

where respiration happens, releasing energy for cell processes

Question 5

ribosomes

Answer 5

(in the cytoplasm, not visible at this size) where proteins are made (protein synthesis)

Question 6

chloroplasts

Answer 6

PLANT ONLY - where photosynthesis takes place making food for the cell

Question 7

cell wall

Answer 7

PLANT ONLY - made of cellulose, tough, supports and keeps the cells shape

Question 8

vacuole

Answer 8

PLANT ONLY - contains cell sap, keeps the cell rigid

Question 9

Bacteria do not have a

Answer 9

nucleus

Question 10

Bacteria have

Answer 10

a flagellum, plasmid and chromosomal DNA

Question 11

Sperm and egg cells contain a

Answer 11

haploid nucleus

Question 12

Light microscope

Answer 12

• uses light to magnify
• colour
• greatest magnification is x2000

Question 13

Electron microscope

Answer 13

• uses electrons to view object
• greatest magnification x10 million
• clearer, more detail
• black and white

Question 14

equation for magnification

Answer 14

magnification (M) = image size (I) ÷ actual size (A)

Question 15

when calculation magnification

Answer 15

measure image in millimetres

multiply by 1000 to find in micrometres (μm)

Question 16

1mm =

Answer 16

1000μm 

Question 17

1m =

Answer 17

10^(3)mm
10^(6) micrometre
10^(9) nanometre
10^(12) picometre

Question 18

parts of a light microscope

Answer 18

eyepiece
objective
stage
coarse and fine focusing wheel

Question 19

label lines must not

Answer 19

cross

Question 20

title diagram with

Answer 20

specimen and magnification

Question 21

enzymes are

Answer 21

biological catalysts (speed up but can be used again) that control reactions in the body, specific to its substrate, affected by temperature, substrate concentration and pH

Question 22

enzymes at lower temps

Answer 22

has less energy so the reaction is slower

Question 23

enzymes are working fastest at

Answer 23

the optimum temperature

Question 24

enzymes at high temps

Answer 24

become denatured and don’t fit the active site

Question 25

rate of reaction =

Answer 25

rate of reaction = 1/time

Question 26

rate of enzyme reactivity v=can be measured by

Answer 26

comparing rate at one pH to another pH

Question 27

solutes

Answer 27

dissolved substances

Question 28

solutes move through cells by

Answer 28

diffusion and active transport

Question 29

water moves through cells by

Answer 29

osmosis

Question 30

diffusion (particles)

Answer 30

particles move form an area of high concentration to an area of low concentration down the concentration gradient through a partially permeable membrane

Question 31

active transport (water)

Answer 31

molecules move form an area of low concentration to an area of high concentration against (up) the concentration gradient through a partially permeable membrane, requires energy from respiration

Question 32

osmosis can be investigated by

Answer 32

calculating change of mass in potatoes in solutes of different concentration

Question 33

equation for change in mass

Answer 33

%change in mass = final mass-initial mass/initial mass x 100% (2d.p.)

Question 34

extended response 6 marks

Answer 34

describe the graph using values

explain clearly each part of the graph