B1

Question 1

How you calculate the size of an object under a microscope?

Answer 1

You would use the formula of I A M

I= Image Size. A= Actual Image Size. M= Magnification

Question 2

What is the Nucleus?

Answer 2

It controls all the activities of the cell and is surrounded by the nuclear membrane. It contains the genes on the chromosomes that carry the instructions for making the proteins needed to build new cells or new organisms. Average diameter= 10 micrometres

Question 3

What is a Cytoplasm?

Answer 3

A liquid gel in which the organelles are suspended and where most of the chemical reactions needed for life take place.

Question 4

What is the Cell Membrane?

Answer 4

Controls the passage of substances such as glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.

Question 5

What is the Mitochondria?

Answer 5

Structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell. They are very small: 1-2 micrometers in length and ONLY 0.2-0.7 in diameter.

Question 6

What are the Ribosomes?

Answer 6

Where protein synthesis takes place,making all the proteins needed in the cell.

Question 7

What do all plants and algal cells have?

Answer 7

They both have Cell Walls which is made of Cellulose and strengthens the cell and gives it support

Question 8

What is a Chloroplast?

Answer 8

They are found in all the green parts of a plant.

Question 9

What is Chlorophyll?

Answer 9

Chlorophyll is the green substance that makes up the Chloroplasts. Chlorophyll absorbs light so the plant can make food by photosynthesis. Each chloroplast is around 3-5 micrometers long

Question 10

What is diffusion?

Answer 10

Diffusion is the spreading out of the particles of a gas, or of any substance in solution(solute). This results in the net movement(overall movement) of particles. The net movement is from an area of HIGHER concentration to LOWER concentration.

Question 11

What is Osmosis?

Answer 11

Osmosis is the net movement of water from a dilute solution (higher) to a concentrated solution (lower) through a semi-permeable membrane

Question 12

What is Active Transport?

Answer 12

Active transport allows cells to move substances from an area of LOW to HIGH concentration. This movement is against the concentration gradient. As a result, cells can absorb ions from very dilute solutions

Question 13

What are eukaryotic cells?

Answer 13

Animals and plant cells are examples of eukaryotic cells.
Eukaryotic cells all have a cell membrane cytoplasm and genetic material that is enclosed in a nucleus.
All animals plants and fungi and Protista are eukaryotes.

Question 14

What are prokaryotic cells?

Answer 14

Bacteria are single celled living organisms.
Prokaryotic cells are 1 to 2 orders smaller of the magnitude to eukaryotic cells.
Bacteria have cytoplasm and a cell membrane surrounded by a cell wall,But the cell wall does not contain the Celulose you see in plant cells.
In prokaryotic cells the Genetic material is not enclosed in a nucleus. The bacterial chromosome is a single DNA loop found free in the cytoplasm.
Prokaryotic cells may also contain extra small rings of DNA called plasmids.
Plasmids code for every specific features such as antibiotic resistance.

Question 15

What are Nerve cells?

Answer 15

Nerve cells are specialised to carry electrical impulses around the body of an animal. They provide a rapid communication system between the different parts of the body.

Question 16

What are the several adaptations of nerve cells?

Answer 16

Lots of dendrites to make connections to other nerve cells.
An axon that carries the nerve impulses from one place to another. They can be very long- the axon of a nerve cell in a blue whale can be up to 25 m long! The longest axon in your body runs from the base of your spine to your big toe.
The nerve endings or synapses are adapted to pass the impulses to another cell or between a nerve cell and a muscle in the body using special transmitter chemicals. They contain loads of mitochondria to provide the energy needed to make the transmitter chemicals.

Question 17

What are muscle cells?

Answer 17

Muscle cells are specialised cells that can contract and relax. Muscles contract and relax in pairs to move the bones of the skeleton for vertebrates can move on land and then water, and in some cases fly.
Smooth muscle cells form one of the layers of tissue in your digestive system and a contract to squeeze the food through your gut.

Question 18

What are the three main adaptions of a muscle cell?

Answer 18

They contain special proteins that slide over each other making the fibres contract.
They contain many mitochondria to transfer the energy needed for the chemical reactions that take place as the cells contract and relax.
They can store glycogen, a chemical that can be broken down and used in cellular respiration by the mitochondria to transfer the energy needed for the fibres to contract.

Question 19

What are sperm cells?

Answer 19

Sperm cells are usually released along way from the egg they are going to fertilise. They contain the genetic information from the male parent. Depending on the type of animal sperm cells need to move through water or the female reproductive system to reach the egg. Then they have to break into the egg.

Question 20

What are the several adaptations of sperm cells?

Answer 20

A long tail whip’s from side to side to help move the sperm through water or the female reproductive system.
The middle section is full of mitochondria, which transfer the energy needed for the tail to work.
The acrosome stores digestive enzymes for breaking down the outer layers of the egg.
A large nucleus contains the genetic information to be passed on.

Question 21

What are root hair cells?

Answer 21

The root hair cells help them to take up water and mineral irons more efficiently.
Root hair cells are always relatively close to the xylem tissue.
The xylem tissue carries water and mineral ions up to the rest of the plant.
Mineral ions are moved into the root hair cell by active transport.

Question 22

What are the three main adaptions for root hair cells?

Answer 22

They greatly increase the surface area available for water to move into the cell.
They have a large permanent vacuole that speeds up the momentum of water by osmosis from the soil across the root hair cell.

Question 23

What are photosynthetic cells?

Answer 23

One of the ways plants differ from animals is that plants can make their own food by photosynthesis.
There are lots of plants so they can carry out photosynthesis-and lots that can’t.

Question 24

What are the number of adaptations in photosynthetic cells?

Answer 24

They contain specialised green structures called chloroplasts contain chlorophyll that trap the light needed for photosynthesis.
They are usually positioned in continuous layers in the leaves and outer layers of the stem of the plant so they absorb as much light as possible.
They have a large permanent vacuole that helps keep the cell rigid as a result of osmosis. When lots of these rigid cells are arranged together to form photosynthetic tissue they help support the stem. They also keep the leaf spread out so it can capture as much light as possible.

Question 25

What are Xylem cells?

Answer 25

Xylem is the transport tissue in plants That carries water and mineral ions from the roots to the highest leaves and shoots. The xylem is also important in supporting the plant.

Question 26

What are the two adaptations in xylem cells?

Answer 26

The xylem cells are alive when they are first formed but a specialist chemical called lignin builds up in spirals in the cell walls.The cells die and form long hollow tubes that allow water and mineral ions to move easily through them, from one end of the plant to the other.
The spirals and rings of lignin in the xylem cells make them very strong and help them stand the pressure of water moving up the plant.They also help support the plants stem.

Question 27

What are Phloem Cells?

Answer 27

Phloem is the specialist transport issue that carries the food made by photosynthesis around the body of the plant. It is made up of Phloem cells that form tutors rather like xylem cells, but Phloem cells do not become lignified and die. The dissolved food can move up and down the Phloem tubes where it is needed.

Question 28

What are the adaptations of the Phloem Cells?

Answer 28

The cell walls between the cells breakdown to form special sieve plates. Please allow water carrying dissolved food to move freely up and down the tubes to where it is needed.
Phloem cells lose a lot of their internal structures but they are supported by the companion cells that help to keep them alive. The mitochondria of the companion cells transfer the energy needed to move dissolved food up and down the plant in Phloem.

Question 29

What is Diffusion?

Answer 29

Diffusion is the spreading out of the particles of a gas, or of any substance in solution. This results in the net movement of particles.The net movement is from a higher concentration to an area of low concentration of the particle. The motion of the particles causes them to bump into each other, and this move them all around.

Question 30

What are the rates of diffusion?

Answer 30

If there is a big difference in concentration between two areas, diffusion will take place quickly. Many particles will move randomly towards the area of low concentration. Only relatively few will move randomly in the other direction. However, If there is only a small difference in concentration between two areas, the net movement by diffusion will be quite slow. The number of particles moving into the area of lower concentration by random movement will only be slightly more than the number of particles that are leaving the area.
Net movement= particles moving in - particles moving out.

Question 31

What is diffusion in living organisms?

Answer 31

Dissolved substances move into and out of cells by diffusion across the cell membrane. These include simple sugars, such as glucose, gases such as oxygen and carbon dioxide, and waste products such as your area from the breakdown of amino acid’s in your liver. The urea passes from the liver cells into the blood plasma and is excreted by the kidneys.

Question 32

What is osmosis?

Answer 32

Osmosis is the net movement of water particles from an area of high concentration to an area of low concentration through a semipermeable membrane.

Question 33

How does osmosis differ from diffusion?

Answer 33

A dilute Solution of sugar contains a high concentration of water (the solvent). It has a low concentration of sugar (the solute).
A concentrated sugar solution contains a relatively low concentration of water and a high concentration of sugar.

Question 34

What is isotonic?

Answer 34

If the concentration of solutes in the solution outside the cell is the same as the internal concentration, the solution is isotonic to the cell.

Question 35

What is hypertonic?

Answer 35

If the concentration of solutes in the solution outside the cell is higher than the internal concentration, the solution is hypotonic to the cell.

Question 36

What is hypotonic?

Answer 36

If the concentration of solutes in the solution outside the cell is lower than the internal concentration, the solution is hypotonic to the cell.

Question 37

What happens if the cytoplasm becomes too dilute in animals?

Answer 37

If the cytoplasm becomes too dilute, because more water is made in chemical reactions, the surrounding fluid becomes hypertonic to the cell and water leaves the cell by osmosis. Osmosis restores the balance in both cases.

Question 38

How is osmosis working in plants?

Answer 38

Plants rely on osmosis to support their stem and leaves.Water moves into plant cells by osmosis. This causes the vacuole to swell, which presses the cytoplasm against the plant cell wall. The pressure builds up until no more water than physically into the cell – this pressure is known as turgor. Turgor pressure makes the cells hard and rigid, which in turn leaves and stems of the plant rigid and firm.

Question 39

What is active transport?

Answer 39

Active transport allows cells to move substances from an area of low concentration to an area of high concentration.

Question 40

How does active transport moving substances?

Answer 40

Energy is needed for the active transport system to carry on molecules across the membrane and then return to its original position. This energy is produced during cell respiration.Scientists have shown in a number of different cells that the rate of respiration and the rate of active transport are closely linked.

Question 41

What is the importance of active transport?

Answer 41

Sugar, such as glucose, it’s always actively absorbed out of your gut and kidney tubules into your blood. This is often done against a large concentration gradient.

Question 42

What is the importance of active transport?

Answer 42

For example, glucose is needed for some respiration so it is important to get as much as possible out of the gut. The concentration of glucose in your blood is kept steady, sometimes it is higher than the concentration of glucose in your gut. When this happens, active transport is used to move the glucose from your gut into your blood against the concentration gradient.

Question 43

What are the adaptations for exchanging materials?

Answer 43

Having a large surface area over which exchange can take place.
Having a thin membrane or being thin to provide a short diffusion path.
In animals, having an efficient blood supply move the diffusing substances away from the exchange services and maintains a steep concentration (diffusion) gradient.
In animals, being ventilated makes gas exchange more efficient by maintaining steep concentration gradient.