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Question 1

How to calculate magnification?

Answer 1

Size of image/size of real object

Question 2

What is a light microscope and what is an electron microscope?

Answer 2

Light microscopes can magnify up to X2000 and have a resolving power of around 20 nm while electron microscopes can magnify up to around X2000000 and have a resolving power of around 0.2 nm.

Question 3

What is a nucleus?

Answer 3

Contains DNA and controls what the cell does.

Question 4

What is a mitochondria?

Answer 4

Releases energy into the cell using glucose and oxygen.

Question 5

What is a ribosome?

Answer 5

Where protein synthesis occurs, making the proteins needed in the cell.

Question 6

What is a cell membrane?

Answer 6

Controls what comes into the cell and controls what comes out of the cell as well as keeping the shape of the cell.

Question 7

What is a cytoplasm?

Answer 7

A gel where organelles are suspended, and where the chemical reactions occur in the cell.

Question 8

What is a cell wall?

Answer 8

Keeps the shape of a plant cell.

Question 9

What is a chloroplast?

Answer 9

Found in all green parts of the plant as they contain chlorophyll, which absorbs light so the plant can do photosynthesis.

Question 10

What is a vacuole?

Answer 10

The space in the cytoplasm filled with cell sap, stores waste and keeps the structure.

Question 11

What is an eukaryotic cell?

Answer 11

They have a cell membrane, cytoplasm and genetic material that is enclosed in a nucleus e.g. plant cell

Question 12

What is a prokaryotic cell?

Answer 12

Cells without a nucleus e.g. bacteria

Question 13

What does a sperm cell do, and what is its structure?

Answer 13

A sperm cell carries the fathers genetics to the egg. It has a long tail, it is streamlines, has lots of mitochondria for energy, half the chromosomes to make a full set and enzymes in the head to get in the egg.

Question 14

What does a xylem cell do, and what is its structure?

Answer 14

They are alive when first formed but lignin builds up in the cell walls, they then die and form tubes that allow water and minerals up from the roots.

Question 15

What does a nerve cell do, and what is its structure?

Answer 15

They carry electrical impulses around the body of an animal. They are long cells, with branches to create a network. They are covered in fat to insulate making it more efficient. The synapses(nerve endings) are adapted to pass the impulses to another cell using special transmitter chemicals, so they contain lots of mitochondria to provide the energy needed to make the chemicals.

Question 16

What does a phloem cell do, and what is its structure?

Answer 16

It transports food that was produced by photosynthesis to where it is needed. They do not become lignified and do not die. The cell walls between the cells break down to form special sieves. These allow water carrying dissolved food to move freely up and down the tubes to where they are needed. They lose a lot of internal structure, but are supported by companion cells that help them stay alive, so they get the mitochondria of the surrounding cells to give them the energy to transport the food up and down.

Question 17

What does a muscle cell do, and what is its structure?

Answer 17

Muscle cells can contact and relax either for movement, to digest food or to pump blood around your body. They are long cells and are layered with lots of mitochondria to transfer the energy needed for the chemical reactions.. They have filaments of protein to cause contraction.

Question 18

What does a root hair cell do, and what is its structure?

Answer 18

A root hair cell absorbs minerals and water from soil. They have a large surface area to absorb water, they have a thin cell wall to allow the water in and a large vacuole for storing water. However they have no chloroplasts as there is no sun where they are in the ground.

Question 19

What does a photosynthetic cell do, and what is its structure?

Answer 19

They are where a plants food is made from photosynthesis. They contain specialised structures called chloroplasts which contain chlorophyll that trap the light needed to photosynthesise. Positioned in continuous layers, so there is the largest surface area.
They have a large vacuole to keep the cell rigid as a result of osmosis, which helps to support the stem.

Question 20

What is diffusion?

Answer 20

The net movement of particles to an area of high to an area of low concentration. Into a cell: oxygen, glucose, amino acids, carbon dioxide(plant cell).Out of a cell: Carbon dioxide(animal cell), waste products e.g. amino acids. The greater the difference in concentration, the steeper the concentration gradient, the faster the rate of diffusion.

Question 21

What is osmosis?

Answer 21

The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Question 22

What is active transport?

Answer 22

Moves substances from a more dilute solution to a more concentrated solution. This is against the concentration gradient. It uses energy released from food in respiration to provide the energy required. It allows plant root hairs to absorb mineral ions from very dilute concentrations in the soil against the concentration gradient.

Question 23

Where are chromosomes found in prokaryotic cells?

Answer 23

They are found in small rings of DNA called plasmids.