Key Concepts In Biology

Question 1

Function of cell membrane

Answer 1

Controls what enters and leaves the cell , e.g . Oxygen, carbon dioxide, glucose

Question 2

Function of nucleus

Answer 2

A large structure that contains genes that control the activities of the cell

Question 3

Function of cytoplasm

Answer 3

Jelly like substance that fills the cell- many reactions take place here

Question 4

Mitochondria

Answer 4

Tiny structures where respiration takes place , releasing energy for cell processes

Question 5

Ribosomes

Answer 5

(Present in the cytoplasm but not visible at this size): where proteins are made (protein synthesis)

Question 6

Animal cell

Answer 6

Cell membrane 
Nucleus 
Cytoplasm 
Mitochondria 
Ribosomes

Question 7

Plant cell

Answer 7

Cell membrane 
Nucleus 
Cytoplasm 
Mitochondria
Ribosomes 
Cell wall 
Central vacuole 
Chloroplasts

Question 8

Bacteria have a simple cell structure. Like animal and plant cell , they have a cell membrane surrounding the cytoplasm. However they do not have a nucleus . These are called prokaryotic cells

Answer 8

Bacteria have …….

Question 9

Bacterial cell

Chromosomal DNA 
Cell membrane 
Ribosomes 
Plasmid DNA 
Cell well 
Flagellum

Answer 9

A single loop of chromosomal DNA lies a free in the cytoplasm.this carries most of the bacterial genes

Controls what enters and leaves the cell

Where proteins are made

Contain additional genes that are not found in chromosomes

For protection , made of different substances to plant cells

To help them move

Question 10

Egg cell

Haploid cell

Ribosomes

Cell membrane

Mitochondria

Answer 10

Egg cell structure and functions ?

Question 11

Sperm cell

Haploid nucleus

Acrosome

Mitochondrion

Tail

Answer 11

Sperm cell structures and function ?

Question 12

Ciliated epithelial cell

Ribosomes

Cytoplasm

Cilia

Mitochondrion

Cell membrane

Nucleus

Answer 12

Cilaited epithelial cell structures and functions

Question 13

Before microscopes were invented about 350 years ago , people could not see the cell in organisms

Magnification enables you too see plant cells , animals cells and bacterial cells and the structures inside them

Light microscope = uses light to view an object . The greatest possible magnification using a light microscope is about x2000

Electron microscope = uses electrons to view an object. This makes it possible to magnify objects up to x10 million. YOU CAN SEE OBJECTS MORE CLEARLY AND IN FAR MORE DETAIL WITH AND ELECTRON MICROSCOPE THAN WITH A LIGHT MICROSCOPE

Answer 13

When we’re microscopes invented ? And what happened ?

Light microscope ??

Electron microscope ??

Which microscope is better to use as it more clear when viewing cells ?

Question 14

Calculating maginification

                    I    -------------------------
           M          R

Measure image in mm

Multiply by 1000 to get measurement in micrometers(um)

Answer 14

How do you calculate image size
How do you calculate magnification

How do you calculate real size

What do you measure image in

What do you multiply by to get measurement in micrometers

Question 15

1000 millimetres =1 metre
1000 micrometers=1 metre 
1000 000 000 nanometres =1 metre
1000 000 000 000 picometres=1 metre 
1000 picometres = 1 nanometre
1000 micrometers= 1 millimetre

Answer 15

How millimetre in a metre ? 
How many micrometers in a metre ? 
How many nanometers in a metre ? 
How many picometres in a metre ? 
How may picometres in a nanometre ? 
How many micrometers In a millimetre ?

Question 16

Rate of reaction - temperature

Enzymes are biological catalysts that control reactions in the body

Each enzyme is specific to its substrate and the activity of enzymes is affected by temperature , substrate and concentration and pH

Optimum temperature = enzyme working at its fastest rate

Higher temperature = cause active site to change shape, so it can’t hold the substrate as tightly and the reaction goes more slowly

Lower temperature=Molecules move more slowly . So substrate molecules take longer to fit in and react in ten active site

Very high temperature = active site breaks up and enzyme is denatured

Answer 16

Optimum temperature effects on temperature ?

Higher temperature efffect on temperature ?

Lower temperature effect temperature ?

Very high temperature effect on active site ?

Question 17

Rate of reaction - substrate concentration

Higher point =Adding more substrate little effect because active site of every enzyme molecule is working

Lower point = not very active site of each enzyme molecule is working , adding more substrate increased rate of reaction

Answer 17

Effect higher point on substrate concentration

Effect lower point on substrate concentration

Question 18

rate calculations for enzyme activity

Calculate relative rate of reaction for a particular pH, as 1
——
Time
Method can be improved by:
- using more accurate measuring apparatus
-taking the mean of several repeats at each pH to help reduce the effect of random variation
-taking measurements over a narrower range of pH

Answer 18

How do you calculate reaction rate ?

How can you improve this Method ?

Question 19

Importance of enzymes

Enzymes catalyse reactions that synthesis larger molecules from smaller ones and break down large molecules into smaller ones

Enzymes as catalysts
Enzymes speed up the rate of a chemical reaction. This means they can be used over and over

Answer 19

What do enzymes do ?

Enzymes as catalysts?

Question 20

Enzymes being transported

Dissolved substances move into and out of cells by diffusion and active Transport . Water moves in and out of cells by osmosis

Diffusion= important in the body . For example, to move oxygen into cells and to remove carbon dioxide
Diffusion= molecules move from higher concentration to lower concentration

Active transport = makes it possible for cells to absorb ions from Very dilute solutions.

Active transport =dissolved molecules move from low concentration to higher concentration

Answer 20

How do dissolved move into and out of cells?

What is diffusion ?
How do molecules move around in diffusion ?
What is active transport?
How do molecules move around in active transport ?