B1 Cell Structure And Transport

Question 1

What is the function of the nucleus?

Answer 1

Controls all the activities of the cell and is surrounded by nuclear memebrane. Contains DNA

Question 2

What is the function of the cytoplasm?

Answer 2

A liquid gel which contains organelles and where most chemical reactions take place

Question 3

What is the function of the cell membrane?

Answer 3

Controls what enters and leaves the cell such as glucose and mineral ions

Question 4

What is the function of mitochondria

Answer 4

Structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell.

Question 5

What is the function of ribosomes?

Answer 5

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

Question 6

What is the function of a cell wall

Answer 6

Rigid,made of cellulose. It supports the cell and strengthens it

Question 7

What is the function of the permanent vacuole?

Answer 7

Contains cell sap, a week solution of suger and salts

Question 8

What is the function of chloroplasts?

Answer 8

Where photosynthesis occurs,which makes food for the plant. They contain a green substance called chlorophyll, which absorbs the light needed for photosynethis

Question 9

What is a prokaryotic cell and give examples.

Answer 9

Cells are small and simple eg bacteria cells

Question 10

What is an eukaryotic cell and give examples.

Answer 10

They are complex cells, eg plant and animal cells

Question 11

What are microscopes?

Answer 11

Microscopes let us see things that we can’t see with the naked eye. The microscopy techniques
we can use have developed over the years as technology and knowledge have improved.

Question 12

What is a light microscope?

Answer 12

Light microscopes use light and lenses to form an image of a specimen and magnily it (make it look bigger). They let us see individual cells and large subcelluler structures, like nuclei.

Question 13

What is an electron microscope

Answer 13

Electron microscopes use electrons instead of light to form an image.
They have a much higher magnification than light
They also have a higher resolution. (Resolution is the ability to distinguish between two points, so a higher recolution gives a sharper inage.)
Electron microscopes let us see much smaller things in more detail, like the internal structure of mitochondria and chloroplast .They even let us see tinier things like ribosomes and plasnids.

Question 14

What is the formula for magnification?

Answer 14

Magnification = image size/real size

Question 15

What is the formula for image size?

Answer 15

Image size = magnification X real size

Question 16

What is the formula for real size?

Answer 16

Real size = image size/magnification

Question 17

How to prepare your slide. (Required practical)

Answer 17

If you want to look at a specimen (e.g, plant or animal cells) under a light microscope, you need to put it on a microscope slide first. A slide is a strip of clear glass or plastic onto which the specimen is mounted.
Here’s how to prepare a slide to view onion cells:
1) Add a drop of water to the middle of a clean slide.
Water drop mixed with sodine
2) Cut up an onion and separate it ouf into layers. Use tweezers to peel off
Cover slip
some spidermal tissue from the bottom of one of the layers.
3) Using the freezers, place the epidermal tissue into the water on the slide.
4) Add a drop of lodice solution. lodine solution is a stain Specimen stained with iodine Slide Stains are used to highlight objects in a cell by adding colour to them.
5) Place a cover slip (a square of thin, transparent plastic on glass) on top. To do this, stand the cover slip upright on the slide, next to the water droplet. Then carefully tilt and lower it so it covers the specimen.
Try not to get any air bubbles under there — they’ll obstruct your view of the specimen.

Question 18

How to prepare a light microscope

Answer 18

1) Clip the slide you’ve prepared onto the stage.
2) Select the lowest-powered objective lens (ie. the one that produces the lowest magnification).
3) Use the coarse adjustment knob to move the stage up to just below the objective lens.
4) Look down the eyepiece. Use the coarse adjustment knob to move the stage downwards until the image is roughly in focus.
5) Adjust the focus with the fine adjustment knob, until you get a clear image of what’s on the slide.
6) If you need to see the slide with greater magnification, swap to a higher-powered objective lens and refocus.

Question 19

What is differentiation?

Answer 19

Its the process by which a cell changes to become specialised for its job

Question 20

What are sperm specialised for?

Answer 20

SPERM CELLS are specialised for REPRODUCTION
The function of a sperm is basically to get the male DNA to the female DNA.
It has a long tail and a streamlined head to help it swim to the egg
There are a lot of mitochondria in the cell to provide the energy needed.
It also carries enzymes in its head to digest through the egg cell membrane.

Question 21

What are nerve cells specialised for?

Answer 21

NERVE CELLS are specialised for RAPID SIGNALLING
The function of nerve cells is to carry electrical signals from one part of the body to another. These cells are long (to cover more distance) and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.

Question 22

What are muscle cells specialised for?

Answer 22

MUSCLE CELLS are specialised for CONTRACTION
The function of a muscle cell is to contract quickly. These cells are long (so that they have space to contract) and contain lots of mitochondria to generate the energy needed for contraction.

Question 23

What are root hair cells specialised for?

Answer 23

ROOT HAIR CELLS are specialised for absorbing WATER and MINERALS
Root hair cells are cells on the surface of plant roots, which grow into long “hairs” that stick out into the soil. This gives the plant a big surface aren for absorbing water and mineral ions from the soil.

Question 24

What are phloem and xylem cells specialised for?

Answer 24

PHLOEM and XYLEM CELLS are specialised for TRANSPORTING SUBSTANCES
Phloem and xylem ceslls form phloem and xylem tubes, which transport subatances such as food and water around plants. To form the tubes, the cells are long and joined end to end. Xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that stuff can flow through them.

Question 25

What is diffusion?

Answer 25

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration,down a concentration gradient until an equilibrium is reached.

Question 26

What is osmosis?

Answer 26

The diffusion of water from a dilute solution to a concentrated solution a partially permeable membrane. (High concentration to low concentration)