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Question 1

What type of cells are animal cells?

Answer 1

Eukaryotic

Question 2

What does eukaryotic mean?

Answer 2

Are membrane bound with a nucleus and cytoplasm.

Question 3

What type of microscope must be used to view ribosomes?

Answer 3

An electron microscope.

Question 4

What is the function of the cytoplasm?

Answer 4

A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It’s where many of the chemical reactions happen.

Question 5

What is the function of the nucleus?

Answer 5

Contains genetic material,including DNA, which controls the cell’s activities.

Question 6

What is the function of the cell membrane?

Answer 6

It is permeable to some substances but not to others and so controls the movement of substances in an out of the cell.

Question 7

What is the function of mitochondria?

Answer 7

Organelles that contain the enzymes for respiration, and where most energy is released in respiration.

Question 8

What is the function of ribosomes?

Answer 8

Tiny structures where protein synthesis occurs.

Question 9

What are most cells?

Answer 9

Specialised and adapted for their function. Animals and plants therefore consist of many different types of cells working together.

Question 10

What are plants made up of?

Answer 10

Plant cells.

Question 11

What are plant cells?

Answer 11

Eukaryotic.

Question 12

What are the sub-cellular structures that animal and plant cells share?

Answer 12

The nucleus, cell membrane, mitochondria and ribosomes.

Question 13

Name and describe the additional sub-cellular plant cell structures.

Answer 13

Chloroplast- organelle that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.
Cell wall- Plant and bacterial cell walls provide structure and protection. Only plant cell walls are made from cellulose.
Permanent vacuole- Filled with cell sap to keep the cell swollen.

Question 14

What are bacterial cells?

Answer 14

Unicellular and prokaryotic.

Question 15

What does prokaryotic mean?

Answer 15

No nucleus so DNA roams free in the cytoplasm.

Question 16

What might larger bacterial cells be visible under?

Answer 16

A light microscope.

An electron microscope would be needed to see the details of the cells organelles.

Question 17

What components of a bacterial cell are unique to bacteria?

Answer 17

Chromosomal DNA- The DNA of bacterial cells is found loose in the cytoplasm. It is called chromosomal DNA and is not contained within a nucleus.
Plasmid DNA- Bacteria also have small, closed-closed-circles of DNA called plasmids present in their cytoplasm. Unlike the chromosomal DNA, plasmid DNA can move from one bacterium to another giving variation.
Flagella- Bacteria can have one or more flagella (singular: flagellum). These can rotate or move in a whip-like motion to move the bacterium.
Cell wall- Plant and bacterial cell walls provide structure and protection. Only plant cell walls are made from cellulose.

Question 18

What happens in sexual reproduction?

Answer 18

In sexual reproduction. the nucleus of an egg cell fuses with the nucleus of a sperm cell to create a fertilised egg, which then develops into an embryo. Both the nucleus of a sperm and egg cell have 23 chromosomes which is half of the amount in a normal body cells- this is why they’re called haploid.
This means that when they fuse, the fertilised egg has the full 46 chromosomes. It’s then diploid.

Question 19

How is an egg cell adapted to its function?

Answer 19

1) It contains nutrients in the cytoplasm to feed and nourish the embryo.
2) It has a haploid nucleus.
3) Straight after fertilisation, the cell membrane changes structure in order to prevent any other sperm from entering. This is so that the embryo has the right amount of DNA.

Question 20

How is a sperm cell adapted to its function?

Answer 20

1) A sperm cell has a long tails so it can swim to the egg.
2) It has lots of mitochondria in the middle section so that it has lots of energy to swim the distance.
3) It also has an acrosome at the front of the ‘head’ . where it sores enzymes needed to digest its way through the membrane of the egg cell.
4) It also contains a haploid nucleus.

Question 21

How is a cilia cell adapted to its function?

Answer 21

1) Epithelial cells line the surfaces of organs.
2) Some of them have cilia on top.
3) Cilia move substances as they beat in one direction to move the substances along the surface of the tissue.

Question 22

What are the following in standard form:
mm
μm
nm
pm

Answer 22

mm = 1 x 10 to -3
μm = 1x 10 to -6
nm = 1 x 10 to -9
pm = 1 x 10 to -12

Question 23

What is the equation that links magnification, image size and real size?

Answer 23

Mag = image/ real.

Question 24

What is the equation for total magnification?

Answer 24

Eyepiece lens magnification x objective lens magnification.

Question 25

How can you test for sugars using benedict's reagent?

Answer 25

1) Add Benedict's reagent to a sample and heat it in a water bath at 75 degrees. If the result is positive, a coloured precipitate will form. 2) The higher the concentration of reducing sugar. the further the colour change goes. (Blue= least to Red= most)

Question 26

What is the starch test for iodine?

Answer 26

Just add iodine solution to the test sample. 1) If starch is present, the sample changes from browny-orange to bluey-black. 2) If no starch is present, the sample stays browny-orange.

Question 27

What is the emulsion test for lipids?

Answer 27

1) Shake the test substance with ethanol for about a minute until it dissolves, then pour the solution into water. 2) If there are any lipids present, they will precipitate out of the liquid and show up as a milky emulsion. 3) The more lipid there is, the more noticeable the milky emulsion is.

Question 28

What is Biuret's test for proteins?

Answer 28

1) First, add a few drops of potassium hydroxide solution to make the solution alkaline. 2) Then add some copper (II) sulfate solution (which is bright blue). - If proteins are present, it will turn purple. - If proteins aren't present, it will stay blue.

Question 29

What does carbohydrase do?

Answer 29

Convert carbohydrates into simple sugars.

Question 30

What does protease do?

Answer 30

Convert proteins into amino acids.

Question 31

What does lipase do?

Answer 31

Convert lipids into glycerol and fatty acids.

Question 32

How can enzymes be used to join molecules?

Answer 32

Organisms need to be able to synthesise carbohydrates, proteins and lipids from their smaller components. Again, enzymes are used in this process. Carbohydrates can be synthesised by joining together simple sugars. Glycogen synthase is an enzyme that joins together lots of chains of glycose molecules to make glycogen (a molecule used to store energy in animals). -Proteins are made by joining amino acids together Enzymes catalyse the reactions needed to do this. -Lots of enzymes are also involved in the synthesis of lipids from fatty acids and glycerol.

Question 33

What is the name for the process of burning food to see how much energy it contains?

Answer 33

Calorimetry.

Question 34

Describe the process of calorimetry.

Answer 34

1) Find a sample of small, dry food. 2) Weigh the food and then skewer it on a mounted needle. 3) Next, add a set volume of water to a boiling tube (held with a clamp)- this will be used to measure the amount of energy that's transferred when the food is burnt. 4) Measure the temperature of the water, then set fire to the food using a Bunsen burner flame. Make sure the Bunsen burner isn't near the water as it could affect the results. 5) Hold the burning food under the boiling tube until the flame goes out. Then set it on fire again and hold it under the boiling tube again - keep doing this until the food can't catch fire . 6) Lastly, measure the temperature of the water again.

Question 35

What is the equation for energy?

Answer 35

Mass x temperature change of water x 4.2

Question 36

How do you work out energy per gram of food?

Answer 36

Energy in food/ mass of food.

Question 37

What is diffusion?

Answer 37

The gradual movement of particles from places of a high concentration of particles to a low concentration of particles. Diffusion happens in both liquids and gases- this is because the particles in these substances are free to move about randomly. Only very small molecules can diffuse through cell membranes- things like glucose, amino acids, water and oxygen. Big molecules like starch proteins can't fit through the membrane.

Question 38

Describe the process of osmosis

Answer 38

Water molecules pass across a partially permeable membrane from an area of high concentration to an area of low concentration. This makes a solution more dilute as there's an approximately even number of water molecules on each side.

Question 39

What is active transport?

Answer 39

The process of moving molecules against the concentration gradient. - This requires energy.