W4 Test - Cells + Biological Molecules

Question 1

What type of microscope creates 3D images? (1)

Answer 1

Scanning electron microscope

Question 2

Explain why Root hair cells contain mitochondria (2)

Answer 2

Aerobic respiration occurs in mitochondria which releases energy which is used for active transport

Question 3

Describe the principles + limitations of using a transmission electron microscope to investigate cell structure (5)

Answer 3

Electrons pass through specimen, the denser parts absorb more electrons, so denser parts appear darker

Cannot look at living material, specimen must be thin, imagine only in 2D (not 3D)

Question 4

What is the function of mitochondria?

Answer 4

Aerobic respiration

Question 5

Why could the structure of organelles seen through a Transmission electron microscope not be seen using a light microscope? (2)

Answer 5

Has low resolution because wavelength of light isn’t short enough

Question 6

What organelle fits this description: found in plants, contains inner membranes, arranged in stacks

Answer 6

Chloroplasts

Question 7

What is the function of chloroplasts?

2

Answer 7

Site of photosynthesis

Question 8

Which organelle fits this description: found in prokaryotic + eukaryotic cells (1)

Answer 8

Ribosomes

Question 9

Suggest why penicillin has no effect on plant cells (1)

Answer 9

A plant cell wall is made of cellulose whereas the prokaryotic cell wall is made form murein

Question 10

Describe the structure of the bacteriophage + bacterium (1)

Answer 10

Bacteriophage - has cell wall

Bacterium - has a capsid

Question 11

Give 2 properties of water and explain its importance in the cytoplasm

Answer 11

High specific heat capacity - creates a stable temp for enzymes

Water very reactive - important for hydrolysis + condensation

Question 12

Other than sodium, name one inorganic ion + give one example of its biological importance in a cell (2)

Answer 12

Magnesium ion - makes chlorophyll

Question 13

What makes up a triglyceride? (2)

Answer 13

Glycerol + fatty acid

Question 14

What bond occurs in a triglyceride? (1)

Answer 14

Ester bond

Question 15

Describe how you would test a liquid sample for the presence of lipid + hou you would recognise a positive result (2)

Answer 15

Emulation test

Put sample and ethanol in test tube, Shake to dissolve substance, pour this into test tube with water

If lipid present, white emulation

Question 16

Describe how a peptide bond is formed between 2 amino acids to form a dipeptide (2)

Answer 16

Condensation reaction between amine group + carboxylic acid group producing molecule of water

Question 17

The secondary structure of polypeptide is produced by bonds between amino acids

Describe how (2)

Answer 17

Hydrogen bonds between NH and CO

Question 18

2 proteins have the same number + type of amino acids but different tertiary structures

Explain why (2)

Answer 18

Amino acids have different sequence

Meaning bonds at tertiary level form in different places

Question 19

What is the main biological molecule in cell membrane (1)

Answer 19

Phospholipid

Question 20

What is the main biological molecule in cell wall (1)

Answer 20

Murein

Question 21

Name the process by which prokaryotic cells divide (1)

Answer 21

Binary fission