exam errors

Question 1

what is the highest res and mag microscope ?1

Answer 1

TEM

Question 2

which microscope had a 3D image ?1

Answer 2

SEM

Question 3

quote res and mag for the following :
-light 
-TEM
-SEM
6

Answer 3

1) light= 0.2um and x1500 mag
2) TEM=0.0002um and x1000 000 and beyond
3) SEM=0.002um and less than x500, 000 ( can examine living specimen )

Question 4

whats the nature of the genetic code ? 3

Answer 4

• triplet code (3 bases = 1AA)
• degenerate (amino acids can have more than one code i.e. : ATG and GGC )
• non overlapping

Question 5

what does rRNA do ?

1

Answer 5

catalyses the formation of peptide bonds ( present in ribosome)
ribosomal RNA

Question 6

whats the difference between cofactor , coenzyme and prosthetic groups ? 3

Answer 6

• co factors = prosthetic groups and coenzymes
• co-enzymes = organic molecules (like a second substrate)
• prosthetic-group = part of the enzymes structure

Question 7

how would you figure out the concentration of reducing sugar in a test tube ? practical q!

Answer 7

1) use a colorimeter; measure absorbance/transmission through coloured tubes; draw a calibration curve and measure X against the curve
2) ensure that excess benedict’s is used, centrifuge the tubes to reveal the amount of blue remaining in the solution and measure the absorbance/transmission through this blue colour, using a red filter).

Question 8

how would you make sure your potometer is set up correctly ?

3

Answer 8

Any three from:
1-ensure shoot is healthy; 
2-cut shoot at an angle; 
3-cut shoot under water; 
4-assemble apparatus under water;
5-ensure leaves are dry; 
6-ensure there are no leaks in apparatus; 
7-ensure there are no air bubbles in apparatus.

Question 9

how would u test if your results match the expected results ?1

Answer 9

Spearman’s rank correlation coefficient

Question 10

2 roles fro mitosis other than growth and repair? 2

Answer 10

1- asexual reproduction 
2-new stem cells 
3-development of body plan 
4-proliferation of white blood cells 
5-gametes from haploid cells
6-new stem cells