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What a cell is

What a cell is

1.[2p]

Why does Pasteur's swan-necked flask experiment support the claim that cells arise only from cells?

Correct
The answer is: Sterile broth open to the air stayed sterile while dust was trapped in the neck, and clouded only when the broth was tipped to touch the dust
The answer is: Sterile broth open to the air stayed sterile while dust was trapped in the neck, and clouded only when the broth was tipped to touch the dust
The answer is: Sterile broth open to the air stayed sterile while dust was trapped in the neck, and clouded only when the broth was tipped to touch the dust

2.[1p]

Hooke's 1665 observations of cork showed living cells.

The answer is: False
Correct

3.[2p]

Using t=x2/2D with D=5×10-10 m²/s, how many seconds does a small molecule take to diffuse 100 µm?

CorrectNot quite: 10

4.[2p]

A cell of radius 1 µm and a cell of radius 10 µm are compared. What happens to the membrane area available per unit of cell contents?

Correct
The answer is: It falls by a factor of ten, since the ratio of surface to volume is $3/r$
The answer is: It falls by a factor of ten, since the ratio of surface to volume is $3/r$
The answer is: It falls by a factor of ten, since the ratio of surface to volume is $3/r$

5.[3p]

Match each quantity for one Escherichia coli cell to its approximate value.

  • Cell volume

  • Protein molecules

  • Genome size

  • Length of its DNA

  • Protein concentration in the cytoplasm

  • 1.6 mm

  • 200 g per litre

  • 1 µm³

  • 3 million

  • 4.6 million base pairs

Show the answer

Cell volume: 1 µm³ Protein molecules: 3 million Genome size: 4.6 million base pairs Length of its DNA: 1.6 mm Protein concentration in the cytoplasm: 200 g per litre

6.[2p]

Which of these are found in bacteria, archaea and eukaryotes alike?

Select all that apply

Correct
Correct
Correct
The answer is: A lipid bilayer boundary, A double-stranded DNA genome, Ribosomes built partly of RNA
The answer is: A lipid bilayer boundary, A double-stranded DNA genome, Ribosomes built partly of RNA

7.[2p]

Put these in order of increasing size.

  1. A skeletal muscle fibre

  2. A bacterium such as E. coli

  3. A typical human cell

  4. A ribosome

Show the answer

a, b, c, d

8.[2p]

Which group did Woese separate from the bacteria in 1977 using ribosomal RNA?

CorrectNot quite: Archaea

9.[2p]

What is the honest reason a mature human red blood cell sits awkwardly with the cell theory?

Correct
The answer is: It has ejected its nucleus, so it cannot divide and cannot give rise to another cell
The answer is: It has ejected its nucleus, so it cannot divide and cannot give rise to another cell
The answer is: It has ejected its nucleus, so it cannot divide and cannot give rise to another cell