Cells, tissues and organs.

Question 1

What is the cytoplasm?

Answer 1

A liquid gel in which most chemical reactions needed for life takes place.

Question 2

What is the mitochondria?

Answer 2

Where most of the energy is released during respiration.

Question 3

What are ribosomes?

Answer 3

Where protein synthesis takes place and all the proteins in the cell are made here.

Question 4

What is the cell membrane?

Answer 4

Controls the passage of substances into and out of cells.

Question 5

Why do plants have cell walls?

Answer 5

Made from cellulose, it strengthens the cell and gives it support.

Question 6

What are chloroplasts?

Answer 6

Chloroplasts are structures found in the green part of a plant, they contain chlorophyll which absorbs light energy in photosynthesis.

Question 7

What is a vacuole?

Answer 7

A space in the cytoplasm filled with cell sap. It is important for keeping cells rigid and supporting the plant.

Question 8

What are bacteria?

Answer 8

Single-celled living microorganisms, which are much smaller than plant and animal cells. They don’t have a nucleus, but ‘genetic material’

Question 9

Why do bacteria have plasmids and a flagella

Answer 9

Plasmids carry extra genetic information

Bacteria use flagella to move themselves around( it is a long protein strand).

Question 10

What are yeast?

Answer 10

Single-celled microorganisms. They reproduce by asexual budding and they are specialised to survive a long time, even when little oxygen is available.

Question 11

What is a specialised cell?

Answer 11

A cell that has a particular structure/feature that is adapted to suit the job it does.

Question 12

How have fat cells adapted?

Answer 12

They have small amounts of cytoplasm and huge amounts of fat. They have few mitochondria and they can expand a lot more than its original size.

Question 13

How are root hair cells adapted?

Answer 13

Large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell.

They are close to the tips of the growing root and therefore xylem tissue which carries water and minerals into the rest of the plant.

Question 14

How are sperm cells adapted?

Answer 14

Long tail whips from side to side and they can swim towards the egg.
The middle section is fully of mitochondria to provide energy for movement.
The acrosomes(head) store digestive enzymes for the breakdown of the outer layers of the egg.
Large nucleus contains genetic information to be passed on.
Streamlined head to help it swim.

Question 15

What is diffusion?

Answer 15

Diffusion is the spreading out of particles from an area of higher concentration to an area of lower concentration.

Question 16

What is the concentration gradient?

Answer 16

The difference between two areas of concentration is the concentration gradient. The bigger the difference, the steeper the concentration gradient, so the faster diffusion will take place.

Net movement= particles moving in- particles moving out.

Question 17

Describe diffusion in living organisms

Answer 17

Water moves across your cell membrane by diffusion( special kind of diffusion which is called osmosis).Also glucose. The amino acids from the break down of proteins in your guts can also pass through cell membranes by diffusion.

The oxygen you need from respiration passes through the air into your lungs. From there it gets into your red blood cells through the cell membrane by diffusion.

Question 18

How can you increase the rate of diffusion by changing the SA?

Answer 18

Folding up the membrane of a cell. The area in which diffusion can take place is increased, therefore the rate of diffusion increases.

Question 19

How have red blood cells adapted?

Answer 19

Concave shape to give them a big SA for absorbing oxygen. They are packed with haemoglobin. They have no nucleus to leave even more room for haemoglobin.

Question 20

How have guard cells adapted?

Answer 20

When there is lots of water available, they go turgid, so the stomata opens and lots of gases exchange for photosynthesis.

When the plant is short of water, guard cells go flaccid to close the stomata and stops water vapour escaping.

Sensitive to light and close at night to save on water.

Adapted to allow gas exchange and control water loss.

Question 21

What is the function of the nucleus?

Answer 21

It contains genes and chromosomes. They carry instructions for making new cells or new cell organisms.

Question 22

What is a tissue?

Answer 22

A tissue is a group of cells with a similar structure working together to carry out a function.

Question 23

What is the function of glandular tissue?

Answer 23

This contains secretory cells that can produce substances such as enzymes and hormones.
In the stomach, the glandular tissue is used to produce digestive juices that break down food.

Question 24

What is the function of muscular tissue?

Answer 24

Muscular tissue contracts to bring about movement. In the stomach it is used churn the food and digestive juices of the stomach together.

Question 25

What is the function of epithelial tissue?

Answer 25

This covers the outside of your body, as well as internal organs.

Question 26

What is the function of the epidermal tissue?

Answer 26

Covers the surface of plants and protects them.

Question 27

What is the function of mesophyll

Answer 27

Contains lots of chloroplasts and carry out photosynthesis.

Question 28

What is the function of of the transport tissues: xylem and phloem?

Answer 28

Xylem transports water and minerals. Phloem transports dissolved foods.

Question 29

What is the function of the leaf, stem and roots?

Answer 29

Leaves for photosynthesis Stem to provide support leaves and flowers. Roots take up water and minerals from the soil.

Question 30

What are organs?

Answer 30

Organs are several tissues working together to perform a job.

Question 31

What are organ systems?

Answer 31

Group of organs that work together to perform a particular function

Question 32

How are egg cells adapted?

Answer 32

Huge food reserves to feed embryo and nourish it in the developing stages. When a sperm fuses with the egg, the egg's membrane instantly changes its structure to stop any more sperm getting in. So the offspring end up with the right amount of DNA

Question 33

How are Palisade cells adapted?

Answer 33

Packed with chloroplasts for photosynthesis. More of them are crammed at the top of the cell- so they're nearer the light. Tall shape means a lot of surface area exposed down the side for absorbing carbon dioxide. Palisade cells are grouped at the top of the leaf, where most photosynthesis happens.

Question 34

What is the digestive system?

Answer 34

An organ system in which humans and other mammals exchange substances with the environment. It breaks down large insoluble molecules into small soluble ones. Digested food is eventually absorbed out of the digestive system and into the blood.

Question 35

What does the digestive system contain?

Answer 35

Salivary glands: produces the enzyme amylase in saliva. Liver: provides bile which neutralises stomach acid and emulsifies fat Large intestine: where water is absorbed from undigested food, leaving faeces. Pancreas: produces digestive enzymes and releases into SI( p,a,l) Gall bladder: where bile is stored before released into SI. Stomach: it pummels the food with its muscular walls. Produces HCL. Rectum: where faeces are stored before they pass through the anus SI: produces digestive enzymes(PAL) to complete digestion, it is also where digested food is absorbed out of the digestive system into the blood.