Prokaryotic Cells (page 15)

Question 1

Prokaryotes are a different kind of cell. you need to be able to compare the contrast prokaryotic and eukaryotic cell.

What is the difference in the size of prokaryotes and eukaryote cells?

Answer 1

Prokaryotes are extremely small cells (less than 2 µm)

Eukaryotes are larger cells (about 10 - 100 µm)

(a micrometer (µm) is one millionth of a metre, or 0.001mm)

Question 2

Explain the different of the DNA for prokaryotes and eukaryotes?

Answer 2

Prokaryotes DNA is circular

Eukaryotes DNA is linear

Question 3

Explain if a nucleus is present or not in prokaryotes and eukaryotes?

Answer 3

Prokaryotes has no nucleus - DNA free in cytoplasm.

Eukaryotes has a Nucleus present - DNA is inside nucleus.

Question 4

What are the cell wall made of in prokaryotes and eukaryotes?

Answer 4

Prokaryotes - the cell wall is made of Polysaccharide, but not cellulose or chitin.

Eukayotes - there is NO cell wall (in animals), cellulose cell wall (in plants) or chitin cell wall (in fungi).

Question 5

Explain the difference with prokaryotes and eukaryotes regarding organells and membrane?

Answer 5

Prokaryotes - has few organells and no membrane-bound orgenelles, e.g. no mitochrondira.

Eukaryotes - has many organells - mitochrondria and other membrand-bound organelles present.

Question 6

Explain the arrangement of flagella when present, what the difference is in prokaryotes and eukaryotes?

Answer 6

Prokaryotes - when present, flagella made of the protein flagellin, arranged in a helix.

Eukaryotes - when present, flagella made of microtubule proteins arranged in a ‘9 + 2’ formation.

Question 7

Explain the size difference of Ribosomes in prokaryotes and eukaryotes?

Answer 7

Prokaryotes - small ribosomes

Eukaryotes - larger ribosomes

Question 8

explain if E coli bacterium is prokaryotes or eukaryotes?

Answer 8

E.coli bacterium is a prokaryotes

Question 9

Is a Human liver cell prokaryotes or eukaryotes?

Answer 9

Human liver cell is Eukaryotes.

Question 10

Are bacterial cells prokaryotic or Eukaryotic?

Answer 10

Prokaryotic.

Question 11

How do you know that a bacterial cell is prokaryotes?

Answer 11

prokaryotes like bacteria are roughly a tenh the size of eukaryotic cells, this means that normal microscopes aren’t really powerful enough to look at their internal structure. Look at diagram on page 15, it shows a bacterial cell as seen under an electron microscope (see page 17). - the diagram shows flagellum, dna, plasma, plasmid ribosome.

Question 12

Some mucus-secreting cells were immersed in a solution of radioactive amion acids. Every five seconds, some of the cells were removed and their organelles were separated and analysed. The radioactivity in the different organelles was measured for each five second interval.

When answering the first two questions below, use organelles from this list ….. golgi apparatus, ribosomes, rough endoplasmic reticulum, vesicles.

a) in which of these organelles would you expect radioactivity to appear first? explain your answer (2 marks)

b) After 5 minutes the golgi apparatus had become radioactive. Which other organells(s) would be radioactive by this time (2 marks)

c) the researchers were particulary interested in the cells’ vesiciles. What is the function of vesicles? (1 mark)

Answer 12

a) Ribosomes (1 mark) because this is where protein synthesis occurs (1 mark)

b) The rough endoplasmic reticulum (1 mark) and some vesicles (1 mark)

c) Vesicles transport substances in and out of the cell and between organelles (1 mark)

Question 13

Give three functions of a cell’s cytoskeleton?

Answer 13

Any three from:

supports the cell’s orgenelles (1 mark)
streghtens the cell/maintains its shape (1 mark)
transports materials around the cell (1 mark)
enables cell movement (1 mark).