Key Concepts in Biology

Question 1

Terra

Answer 1

x 10^12

Question 2

Giga

Answer 2

x 10^9

Question 3

Mega

Answer 3

x 10^6

Question 4

Kilo

Answer 4

x 10^3

Question 5

Centi

Answer 5

x 10^-2

Question 6

Milli

Answer 6

x 10^-3

Question 7

Micro

Answer 7

x 10^-6

Question 8

Nano

Answer 8

x 10^-9

Question 9

Pico

Answer 9

x 10^-12

Question 10

Modern light microscopes compared to Hooke

Answer 10

Eyepiece lens magnifies the image (x10 magnification) - more clarity meaning scientists can understand sub-cellular structures
Hooke was only x30
Objective lenses are x4, x10 and x40
Better resolution (0.0001mm compared to 0.002mm)
- smallest distance between two points that can be seen
- more detail can be seen

Question 11

Electron microscopes

Answer 11

x2 000 000 magnification and better resolution - see smaller specimens in more detail

Question 12

Eukaryotes

Answer 12

Have a nucleus

Question 13

Prokaryotes

Answer 13

Don’t have a nucleus

Question 14

Animal cells (5 structures)

Answer 14

Cell membrane, nucleus, mitochondria, ribosomes, cytoplasm

Question 15

Plant cells (8 structures)

Answer 15

Chloroplasts, mitochondria, ribosome, cytoplasm, cell wall, cell membrane, vacuole, nucleus

Question 16

Nucleus

Answer 16

Contains DNA (genetic information in chromosomes) and controls activities of the cell

Question 17

Cell membrane

Answer 17

Controls what goes in and out the cell

Question 18

Cytoplasm

Answer 18

Where chemical reactions take place

Question 19

(Large) Vacuole

Answer 19

Made of sap and gives the cell a rigid structure

Question 20

Cell wall

Answer 20

Made of cellulose for support and to stop the cell from bursting

Question 21

Bacteria (7 features)

Answer 21

Chromosomal DNA, plasmid DNA, cell membrane, ribosomes, flagella, chitin cell wall, slime capsule

Question 22

Sperm cells adaptation

Answer 22

Acrosome (contain enzymes to break down egg’s jelly coat), haploid nucleus (23 chromosomes), mitochondria (release lots of energy from aerobic respiration for aprèm to swim), flagellum (allows sperm to swim to egg)

Question 23

Ciliates epithelial cells adaptations

Answer 23

Have cilia (hair like structures) to move fertilised egg towards the uterus. Mitochondria to release energy from aerobic respiration for cilia to move.
Also found in airways to move mucus away from the lungs

Question 24

Enzyme

Answer 24

Biological catalysts which speed up the rate of a break down or synthesis reaction, whilst remaining chemically unchanged

Question 25

How do enzymes denature

Answer 25

The active site changes shape due to molecules excessively bumping into it because more heat energy gives them more kinetic energy meaning the substrate can no longer fit

Question 26

Enzyme action

Answer 26

By raising the temperature, this speeds up the reaction as the heat energy is transferred as kinetic energy so the rate of enzyme action is quicker. The active site is a specific shape so it can only fits into certain substrates (lock and key)

Question 27

Active site + substrate

Answer 27

Enzyme substrate complex

Question 28

Substrate

Answer 28

The thing that is changed in the reaction

Question 29

Active site

Answer 29

Where the substrate joins to the enzyme

Question 30

Optimum pH in enzyme action

Answer 30

(Usually 7) If it is too high or too low, it interferes with the bonds holding the enzyme together, thus changing the shape

Question 31

Rate of enzyme reaction

Answer 31

Amount of reactant used or amount of product formed / time taken

Question 32

Carbohydrases

Answer 32

Break down carbohydrates from starch to sugar (glucose) e.g. Amylase in saliva pH 6

Question 33

Proteases

Answer 33

Break down proteins into amino acids e.g. Pepsin in the stomach pH 2

Question 34

Lipase

Answer 34

Break down lipids into glycerol and fatty acids

Question 35

Active transport

Answer 35

The movement of molecules from an area of low concentration to an area of high concentration (against the concentration gradient) and requires energy from respiration