AS

Question 1

Compare transmission electron microscope and scanning electron

Answer 1

TEM>SEM higher resolution
TEM- shows the cells organelles and displays the cell interior
SEM- shows the surface and the 3D image

Question 2

Describe how neutrophils,erythrocytes,squamous and ciliated epithelial cells is specialised

Answer 2

Neutrophils - many lysosomes,multi-lobed nucleus, for immune response, destroy pathogens
Erythrocytes- flattened disc,no nucleus, space for haemoglobin, flexible to squeeze through vessels
Squamous epithelium - flattened shape
very thin / (form layer) one cell thick, rapid diffusion
Ciliated
have cilia / ‘hair like’ structures which, move / beat
Waft mucus

Question 3

Why do goblet cells contain mitochondria and Golgi apparatus

Answer 3

Required to produce ATP

to package protein

Question 4

What is meant by the term esterification

Answer 4

Condensation reaction, loss of water molecule

Reaction between glycerol and fatty acids

Question 5

What is meant by autoimmune disease

Answer 5

When the immune system stops recognising self cells/tissue starts destroying

Question 6

What is the role of agglutination

Answer 6

Clumps pathogens together
Stops pathogens moving
Too big to enter cell

Question 7

Outline the sequence of vaccination

Answer 7

Step 3- antigen binds to a specific B or T lymphocytes
Step 4- colonial proliferation
Step 5- t memory cells,stored in tissues, immunological memory cell, secondary immune response

Question 8

What is the correct stage of mitosis

Answer 8

1- G2
2- Mitosis 
3- cytokinesis 
4- g1 
5- S

Question 9

Describe how a colorimeter is calibrated and why is it important to calibrate a colorimeter

Answer 9

Set to zero absorbency using blank distilled water

To ensure that everything is accurate and valid by measuring same standards

Question 10

What do you find in a xylem tissue from a stem of a dicotyledonous plant

Answer 10

Vessel wall
Lumen
Pit

Question 11

Name the covalent chemical bond labelled In the tertiary structure of the enzyme lysozyme

Answer 11

Disulphides
Alpha helix
Quaternary

Question 12

Name the molecule that is found in the cells walls of bacterial cells

Answer 12

peptiglycagon

Question 13

Suggest that type of chemical bind that lysozyme breaks and name the molecule other then the substrate that is needed for this reaction

Answer 13

Glycosidic

Water

Question 14

Identify the type of phloem cell into which the stylet is inserted to obtain the sap.

Answer 14

Sieve tube

Question 15

Explain why starch is not transported in the sap

Answer 15

Starch is insoluble therefore it doesn’t dissolve in water

Question 16

Suggest why sucrose is a more suitable transport molecule than glucose

Answer 16

Unloading from source for sink

Less reactive and used up for aerobic respiration

Question 17

Explain why it is important to use a differential stain when examining a blood smear under the microscope.

Answer 17

To see the difference between cells and organelles, contrast

Ensures WBC to be counted because they are transparent

Question 18

Evaluate the scientist’s conclusion with reference to genetic biodiversity and species biodiversity.

Answer 18

genetic biodiversity:
genetic, diversity / variation, low / will decrease
small gene pool / few alleles (at each locus)
species biodiversity
wildcats may go extinct (in Scotland)
one less species correct ref. to species richness
correct ref. to species evenness

Question 19

What is the term used to describe the difference between the two populations of a wildcat

Answer 19

Intra specific variation

Question 20

Describe and explain the precautions that need to be taken when setting up and using the apparatus in Fig. 4.1 to ensure that no air is present.

Answer 20

setting up:
• D cut stem under water
• D have apparatus under water • D insert stem under water
• D joint(s) must be, sealed / tight
using:
• D do not allow the bubble to move too far
• D use syringe to move bubble
• E so air bubble does not enter, xylem / stem • E so same air bubble can be re-used

Question 21

Describe the structure of the RER

And the role of the membrane

Answer 21

Molecules form a phospholipid bilayer, flattened sacs and covered in ribosomes,
Hold ribosomes in place
Barrier between organelle and cytoplasm for specific metabolic reaction

Question 22

Explain how the nucleotides in a DNA molecule are arranged as two polynucleotide strands

Answer 22

Joined together by phosphodiester bond

2 hydrogen bonds between complementary bases AT