SB1

Question 1

How do you work out magnification?

Answer 1

Magnification = size of image ÷ actual size of specimen

Question 2

Name a difference between light microscopes and electron microscopes

Answer 2

A few answers:
Light rays and beams of electrons
Magnify up to 2000x and magnify up to 50 million times
3 objective lenses and no glass lenses

Question 3

What is resolution?

Answer 3

The ability to distinguish two objects from each other

Question 4

Convert 1cm into nm

Answer 4

10000000nm

Question 5

What is the core practical for microscopes?

Answer 5

1) Collect a small specimen of the cell
2) Add a drop of water or stain in the centre of the slide
3) Place your specimen on it
4) Lower a coverslip over it with a toothpick
5) Examine your specimen under a microscope

Question 6

What is in an animal cell?

Answer 6

Cytoplasm, Cell membrane, Nucleus, Mitochondria, Ribosomes

Question 7

What is in a plant cell?

Answer 7

Cell wall, Vacuole, Cytoplasm, Mitochondria, Ribosomes, Cell membrane, Nucleus, Chloroplast

Question 8

What is the job of ribosomes and mitochondria?

Answer 8

Ribosomes : Make new proteins for a cell

Mitochondria : Jelly-bean shaped structures in which aerobic respiration occurs

Question 9

Compare animal cells and plant cells

Answer 9

Both animal cells and plant cells contain a cell membrane, cytoplasm, nucleus, ribosomes and mitochondria. Both are eukaryotic meaning they have a nucleus. However, plant cells also have a vacuole, cell wall and chloroplast.

Question 10

What is the difference between the cell wall and the cell membrane?

Answer 10

The cell wall supports and protects the cell, where as the cell membrane controls what enters and leaves and also separates one cell from another.

Question 11

Name two specialised cells

Answer 11

Anything like:
Pancreatic cell 
Intestine cell 
Egg cell 
Sperm cell 
Ciliated epithelial cells

Question 12

Describe and compare sperm cells and ciliated epithelial cells

Answer 12

Sperm cells have a streamlined shape, tail, and a large number of mitochondria to help them swim fast. They have a haploid nucleus and a vacuole called the acrosome at the tip of its head.
Ciliated epithelial cells line the structure of the body, cilia are covered in cell membrane and contain strands of a substance that can contract and cause wavy movement.
A similarity is the hair-like cilia are like short sperm cell tails and wave from side to side but instead of helping them swim they sweep substances along. They also both have a nucleus so are eukaryotic cells.

Question 13

Describe bateria

Answer 13

Bacteria are prokaryotic so have no nucleus, instead the cytoplasm contains one loop of chromosomal DNA called plasmids. They have plasmid, chromosomal DNA, a slime coat, flagellum, flexible cell wall, cytoplasm and a cell membrane.

Question 14

In humans, what do digestive enzymes do?

Answer 14

They turn large molecules of food into smaller subunits, so they are small enough to absorbed by the small intestine.