WRONG Qs- Term 1 Flashcards
Function of endoplasmic reticulum (1 mark):
Protein synthesis
Function of Golgi apparatus (1 marks):
Modifying protein (adds carbs to protein) making a glycoprotein
Describe the structure and function of the nucleus (4 marks):
Structure:
- double membrane AND pores
- chromosomes
- nucleolus
Function:
- holds genetic information for polypeptides
- DNA replication occurs
- production of mRNA
Explain why the organelles visible in the photograph would not have been visible in an optical light microscope (2 marks):
1) low resolution
2) because wavelength of light is not short enough
Describe how you could make a temporary mount of a piece of plant tissue to observe the position of starch grains in the cells when using an optical (light) microscope (4 marks):
1) add a drop of water to glass slide
2) obtain thin section and place on slide
3) Stalin with iodine in potassium iodide
4) lower cover slip using mounted needle
Describe how a peptide bound is formed between two amino acids to form a dipeptide (2 marks):
1) a condensation reaction- loses a water molecule
2) formed between an amine and hydroxyl group
Describe how the secondary structure of a polypeptide is produced by bonds between amino acids (2 marks):
1) hydrogen bonds
2) between NH and C=O group
Explain why two proteins have the same number and type of amino acids but different territory structures (2 marks):
1) different primary structure
2) form disulphide bonds in different places
Compare and contrast the structure of starch and cellulose (6 marks):
1) starch is bigger and cellulose is smaller
2) starch contains A- glucose and cellulose contains B-glucose
3) both are glucose polymers
4) both contain glycosidic bonds
5) both contain hydrogen, carbon and oxygen only
6) both contain glucose
7) starch is coiled, cellulose is straight
Describe how a triglyceride molecule is formed (3 marks):
1) formed between glycerol and three fatty acids
2) ester bond is formed
3) condensation reaction forming 3 molecules of water r
Describe how the structure of glycogen is related to it’s function (6 marks):
1) helical so compact
2) branched- more enzymes- faster hydrolysis
3) polymer of glucose so easily hydrolysed
4) large, insoluble molecules do not affect the water potential of the cell
5) glucose polymer so provides respiratory substrate for enzymes
Protein associated with DNA in a chromosome:
His tone
Describe the role of DNA polymerase in the semi-conservative replication of DNA (3 marks):
1) joins adjacent DNA nucleotides
2) catalyses condensation reactions
3) catalyses formation of phosphodiester bonds between nucleotides
Contrast how an optical microscope and a transmission electron microscope work and contrast the limitations of their use when studying cells (6 marks):
1) TEM use electrons and optical use light
2) TEM allows for greater resolution so smaller organelles can be observed
3) TEM views only dead/ dehydrated specimens and optical can view live specimens
4) TEM does not show colour, optical can
5) TEM requires a thinner specimen
6) TEM requires a more complex/ time consuming preparation
Describe binary fission in bacteria (3 marks):
1) replication of circular DNA
2) replication of plasmids
3) division of cytoplasm to produce daughter cells
Describe the role of spindle fibres during mitosis (2 marks):
1) attachment of centromeres
2) separation of centromeres
Describe the difference between pre-mRNA and mRNA molecules (2 marks):
1) mRNA has fewer nucleotides, pre-mRNA has more nucleotides
2) mRNA has no introns, only exons, pre-mRNA has both because of splicing
Describe how you would use cell fractionation techniques to obtain a sample of chloroplasts from leaf tissue (do NOT include in your answer information about any solutions) (3 marks):
1) macerate/ homogenise
2) centrifuge
3) at increasing speeds until chloroplast fraction obtained
Describe three properties of this solution and explain how each property prevented damage to the organelles (3 marks):
1) ice cold, prevents enzyme activity
2) buffered, prevents enzymes from denaturing
3) same water potential, prevents bursting of organelles
Describe and explain how cell fractionation and ultracentrifugation can be used to isolate mitochondria from a suspension of animal cells (5 marks):
1) cell homogenisation to open cells
2) filter to remove large debris
3) use isotonic solution to prevent damage to mitochondria
4) keep cold to reduce damage by enzymes
5) centrifuge at a lower speed to separate nuclei
6) re-spin after nuclei at a higher speed to get mitochondria at bottom of tube
Describe the principles and limitations of using a transmission electron microscope to investigate the cell structure (5 marks):
1) electrons enter thin specimen
2) denser parts absorb more electrons
3) so denser parts appear darker
4) cannot look at living material
5) specimen must be very thin
Describe the role of one named organelle in digesting bacteria (3 marks):
- lysosomes
- fuse with vesicles
- release hydrolytic enzymes
Describe how the process meiosis results in haploid cells (4 marks):
- DNA replication
- two divisions
- separation of homologous chromosomes in first division
- separation of sister chromatids in second division
- produces 4 haploid cells
Describe how a sample of chloroplasts could be isolated from leaves (4 marks):
1) break open cell tissue + filter
2) put in a solution which is cold, sam pH, same water potential
3) centrifuge and spin
4) centrifuge at a higher speed so chloroplasts move out
Give three structural features found in all virus particles and describe the function of one (2 marks):
- genetic material, capsid, attachment protein
- genetic material codes for viral protein
Explain why viruses are described as acellular and non- living (2 marks):
Acellular- no cell-surface membrane
Non living- no metabolic reactions
Describe how HIV is replicated (4 marks):
1) attachment proteins attach to receptors on helper T cell
2) nucleic acid enters cell
3) reverse transcriptase converts RNA to DNA
4) viral protein produced
5) virus particles assembled and released from cell
Why is the coverslip pressed down in RP2? (2 marks)
- create a thin layer of cells
- so light can pass through
What is a tumour? (2 marks)
A large mass of cells with uncontrolled mitosis
