Key Concepts in Biology

Question 1

Eukaryotic cell definition

Answer 1

Cell with a membrane-bound nucleus

Question 2

Prokaryotic cell definition

Answer 2

Cell with no membrane-bound nucleus

Question 3

Subcellular structures of animal cell

Answer 3

Nucleus
Cytoplasm 
Ribosomes
Mitochondria
Cell membrane

Question 4

Subcellular structures of plant cell

Answer 4

Nucleus
Cytoplasm
Ribosome
Cytoplasm
Cell membrane 
Mitochondria
Vacuole
Cell wall
Chloroplasts

Question 5

Subcellular structures of bacteria

Answer 5

Chromosomal DNA
Plasmid DNA
Ribosomes
Cell membrane
Cytoplasm
Flagellum
Cell wall

Question 6

Nucleus definition and purpose

Answer 6

contains genetic material arranged as chromosomes

controls cells in activities

Question 7

Cytoplasm definition and purpose

Answer 7

gel-like substance where chemical reactions occur

contains enzymes

Question 8

cell membrane definition and purpose

Answer 8

holds cell together

controls what goes in and out of cell

Question 9

mitochondria definition and purpose

Answer 9

where aerobic respiration occurs

Question 10

Ribosomes definition and purpose

Answer 10

Where translation of genetic material for protein synthesis occurs

Question 11

Cell wall definition and purpose

Answer 11

rigid, made of cellulose

supports and strengthens cell’s structure

Question 12

Vacuole definition and purpose

Answer 12

contains sap

maintains internal pressure to support cell

Question 13

Chloroplast definition and purpose

Answer 13

contains chlorophyll

where photosynthesis occurs

Question 14

Chromosomal DNA definition and purpose

Answer 14

one long circular chromosome
controls activities of cell
floats freely on cell

Question 15

Plasmid DNA definition and purpose

Answer 15

small loops of extra DNA
contains genes for things such as drug resistance
can be passed between bacteria

Question 16

Flagellum definition and purpose

Answer 16

long, hair-like structure that makes cell move

can be used to move bacteria away from harmful substances

Question 17

haploid definition

Answer 17

contains half of the chromosomes in organism

Question 18

Egg cell adaptations

Answer 18

Contains nutrients in cytoplasm to feed embryo
Haploid nucleus
Membrane changes shape to prevent other sperm to enter straight after fertilisation

Question 19

function of egg cell

Answer 19

carry female DNA

nourish embryo during early stages

Question 20

function of sperm

Answer 20

transport male’s DNA to egg cell

Question 21

Speed cell adaptations

Answer 21

Long tail to swim to egg cell
Acrosome containing enzymes to get through egg cell membrane
Haploid nucleus
Lots of mitochondria to supply lots of energy to get to egg cell

Question 22

Ciliated epithelial cell function and adaptations

Answer 22

have hair-like structures to move substances in one direction

Question 23

Resolution definition

Answer 23

how well two points are distinguished

higher resolution = more clearly, in more detail

Question 24

Light microscopes facts

Answer 24

Uses light
Resolution and magnification depends on quality and is lower than electron microscope
can be used to inspect living cells
can see large organelles like nuclei and chloroplasts

Question 25

Electron microscope facts

Answer 25

Uses electrons Higher magnification and resolution than light microscopes Can’t inspect living cells

Question 26

total magnification formula

Answer 26

total magnification = eyepiece lens magnification x objective lens magnification

Question 27

magnification formula

Answer 27

magnification = image size / real size

Question 28

Enzyme definition

Answer 28

Catalysts made by organisms

Question 29

Purpose of enzymes

Answer 29

To speed up useful / specific chemical reactions in organisms

Question 30

Enzyme method

Answer 30

substrate collides into enzyme in right angle it becomes attached to enzyme active site substrate becomes split apart / combines with other substrates

Question 31

What affects enzymes in rate of reaction

Answer 31

Temperature (too hot = denature) ph (extreme pH = denature) substrate concentration

Question 32

Breaking down of carbohydrates

Answer 32

carbohydrate (starch) -> amylase (enzyme) -> simple sugars (e.g. maltose)

Question 33

Breaking down of proteins

Answer 33

Protein -> protease (enzyme) -> amino acids

Question 34

Breaking down of lipids

Answer 34

Lipid (fat) -> lipase (enzyme) -> fatty acids and glycerol

Question 35

Test for sugars method

Answer 35

Add blue Benedict’s reagent to sample Heat solution in water bath to ~75° If positive, coloured precipitate is formed (solid particles in solution) Higher concentration = colour closer to red

Question 36

Test for starch method

Answer 36

Add brown iodine into solution | If positive, solution will turn blue-black

Question 37

Test for lipids method

Answer 37

Shake sample with ethanol until dissolved Poor solution into water If positive, milky substance will form on top of water More lipid = milkier colour

Question 38

Test for protein

Answer 38

Add potassium hydroxide solution to make solution alkaline Add bright blue copper sulphate solution If positive, solution will be purple

Question 39

Energy in food (formula)

Answer 39

Energy in food (J) = mass of water (g) x temperature change x 4.2

Question 40

Diffusion definition

Answer 40

Gradual movement of particles from higher concentration to lower concentration Happens in liquids and gases Down concentration gradient Passive (low energy)

Question 41

Osmosis definition

Answer 41

Movement of water across partially permeable membrane from higher concentration to lower concentration Down concentration gradient Passive (low energy)

Question 42

Active transport definition

Answer 42

Movement of particles across membrane from lower concentration from higher concentration Requires energy Against concentration gradient Active (more energy)