Topic 1 - Key Concepts in Biology

Question 1

Draw and label animal, plant and bacteria cell

Answer 1

Answer on card 1

Question 2

Explain how an egg cell is specialised in its function and explain its function

Answer 2

The main function of the female DNA is to carry and to nourish the developing embryo in its early developing stages.
1.) It contains nutrients in the cytoplasm to feed the embryo.
2.)Straight after fertilisation , its membrane changes structure to stop any more sperm
getting in.
3.) Contains a haploid nucleus.

Question 3

What are specialised cells?

Answer 3

Cells that are able to adapt to their function.

Question 4

Describe two differences between prokaryotic and eukaryotic cells

Answer 4

1. ) Eukaryotic cells have a nucleus, prokaryotic cells don’t.
2. ) Prokaryotic cells is unicellular, but eukaryotic cell is multicellular.

Question 5

Explain how a sperm cells is specialised in its function and describe its function

Answer 5

Its function is to the male’s DNA to the females egg.

1. ) Has a long tail so it can swim
2. ) Has a lot of mitochondria in the middle section , for energy to swim
3. ) Acrosome on the front of the head, where it stores enzymes
4. ) Contains a haploid nucleus

Question 6

Explain how the ciliated epithelial cell is specialised in its functions

Answer 6

The function of the cell is to move substances.

1. ) Have cilia on the top surface of the cell
2. ) Large surface area and they line on surfaces of organs.

Question 7

What does resolution mean?

Answer 7

How well a microscope distinguishes between two points that are close together. Higher resolution means the image is in more detail and is more clear.

Question 8

Explain and how you would use a microscope to see something

Answer 8

Answer on CARD 2

Question 9

Equation for working out the total magnification

Answer 9

Total magnification = eyepiece lens X
objective
lens
magnification

Question 10

The magnification triangle for equations

Answer 10

Image size

Magnification X Real size

Question 11

Converting units

Answer 11

Millimetre (mm)
X1000 Micrometre9(um) divide 1000
down Nanometre (nm) up
Picometre (pm)

Question 12

Enzymes- Explain how temperature, ph and concentration affect the rate of reaction

Answer 12

Temperature- Higher temperature increases the rate of reaction at first , but then it gets too hot and the bonds break causing the enzyme to denature
Ph- if its too high or low the active site changes shape causing the enzyme to denature
Concentration - the higher the substrate concentation the higher the rate of reaction but up to a certain point adding more makes no difference.
GRAPHS ON CARD 3

Question 13

Investigate effect of ph on enzyme activity and name control variables

Answer 13

1.)Put a drop of iodine solution into every well of the spotting tile
2.) Set up a Bunsen burner ( using a tripod, gauze) put the beaker on top of the tripod and heat the water until its 35C (constantly)
3.)Using a syringe add 3cm of amalyse solution and 1cm of buffer solution at ph 5 to a boiling tube
4.) Using a different syringe add 3cm of starch solution
5.)Immediately mix it and start the stop clock
6.) Use continuous sampling to measure how long it takes amalyze to break down (every 10 sec)
7.) Then repeat the experiment using different ph values
Control variables : concentration , volume of amalyze solution

Question 14

How to calculate the rate of reaction formula and its units

Answer 14

Rate= 1000 divide time (s-1)

Question 15

Different types of enzymes break down carbohydrates, proteins and lipids

Answer 15

Starch —> Amalyse enzyme—> Maltose,
other sugars
Proteins–> Protease enzymes –> amino acids
Lipid–> Lipase –> Glycerol and fatty acids

Question 16

Enzyme that joins lots of chains of glucose molecules to make glycogen is called…

Answer 16

Glycogen synthase

Question 16

Enzyme that joins lots of chains of glucose molecules to make glycogen is called…

Answer 16

Glycogen synthase

Question 17

How can you test for sugars

Answer 17

Benedict’s reagent : add it to a sample and heat it up to 75C . If its positive it will form a coloured precipitate. The higher the concentration of the reducing sugars the further the colour chnage goes ( from blue to red brick)

Question 18

How do you test for lipids ?

Answer 18

Use the Emulsion test: shake the test substance with ethanol , if lipids are present a milky emulsion will form

Question 19

How do you test if protein is present in a substance?

Answer 19

Use the biuret test: first add potassium hydroxide solution to make it alkaline. Then add copper sulphate solution(blue). If protein is present then the solution will turn purple.

Question 20

Equation to calculate energy in food

Answer 20

Energy in food(J)= Mass of water(g) X 4.2

Question 21

Equation to find out energy per gram of food

Answer 21

energy per g of food(J/h)=energy in food(J)
divide
mass of food (g)

Question 22

What is diffusion?

Answer 22

Is the net (overall) movement of particles from an area of high concentration to an area of lower concentration.

Question 23

What is osmosis ?

Answer 23

Is the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.

Question 24

What is active transport ?

Answer 24

Is the movement of particles across a membrane against a concentration gradient (lower to higher concentration) using energy transferred during respiration.

Question 25

Explain how you would investigate osmosis practical ?

Answer 25

1.) Prepare sucrose solutions of different concentrations.
2.) Then cut the potatoes roughly same size with diameter of 1cm into cylinders.
3.)Then divide the cylinders into groups of three and use a mass balance to measure the mass of each group.
4.)Place one group in each solution and leave it there for 40min.
5.)Then remove the cylinders and pat dry them.
6.) Then weigh each group and record your results.
(the only thing you need to change in this experiment is the sucrose solution concentration)

Question 26

What is the equation to work out the percentage change?

Answer 26

Percentage change=final mass- initial mass
DIVIDE X100
initial mass