What are cells?

Question 1

what are the 2 types of cells?

Answer 1

prokaryotic and eukaryotic

Question 2

what are 4 ways in which cells are linked to illness?

Answer 2

• Inherited cell malfunctions
• Pathogenic illness cause cells to malfunction
• As you get older cells start to malfunction
• Environment (poison or toxin) disrupt the normal function of cells
  
  • Disrupting the normal function of cells lead to diseases

Question 3

give 2 examples of drugs that are linked to cells?

Answer 3

• antibiotics disrubt bacterial cells
• chemo kills fast growing (bad) cells

Question 4

what are 3 features of a virus?

Answer 4

• Lots of proteins around the surface
• Some viruses have a membrane
• Inside there are a few more protein and some nucleic acids (RNA or DNA)

Question 5

what do virsues need to “be alive”?

Answer 5

in contact with a cell

Question 6

how do virsues infect a cell? (4 steps)

Answer 6

• Viruses bind to a molecule on the surface of some cells
• It then tricks the cell into thinking its something the cell should want
• The cell then takes the virus inside
• The virus then hijacks some of the cells machinery

Question 7

what 3 things does the virus use the cells for?

Answer 7

• It get the cell to make more viral proteins
• The cell copies the viral genome
• The cell assembles all sorts of new viruses

Question 8

why is life hard to define?

Answer 8

• some things you’d expect alive things t do can be done by things that are not alive (wild fires can grow)
• some things you know are alive can’t meat some of the conditions for life (mules can’t reproduce)

Question 9

what were the 3 conditions of life according to sir Paul nurse?

Answer 9

• Evolution through natural selection
• Separated from their environment by a boundary (e.g. membrane)
• Metabolically active and use their metabolism to maintain themselves, grow and reproduce.

Question 10

why do virsues cycle between alive and not-alive under sir Paul Nurse’s definition of life?

Answer 10

• viruses are not metabolically active unless they are in a cell
• alive when in cell
• dead outside of cells

Question 11

what are the 2 prokarotic cell types?

Answer 11

bacteria and archaea

Question 12

what are the 2 key feature of prokaryotic cells?

Answer 12

• lack a nucleus
• don’t have much internal structure

Question 13

how do eukaryotic cells compare to prokaryotic cells?

Answer 13

• much larger and more complex
• membrane bound organelles (such as nucleus)
• organelles perform specialised functions

Question 14

what are all cells surrounded by?

Answer 14

membranes made of lipids (and other things)

Question 15

what can all cells do?

Answer 15

sense and respond to there environment

Question 16

what is the function of DNA (in the form of genes)?

Answer 16

carries the instructions for building proteins

Question 17

what are the 6 common roles of proteins in cells?

Answer 17

• including structural support
• communication
• repair
• catalysing reactions
• recycling
• making new organelles and cell

Question 18

why do viruses need larger cells to replicate?

Answer 18

too small to function on their own

Question 19

what is the average volume of a prokarotic cell?

Answer 19

~ 1 mm^3

Question 20

what is the average volume of an eukaryotic cell?

Answer 20

~ 1000 mm^3

Question 21

why do larger cells compartmentalise?

Answer 21

• Diffusion of molecules in large volumes limits the speed at which reactions can occur.
• If there was no organisation in eukaryotic cells the required chemical reactions would occur much slower in eukaryotes than they do in prokaryotes.

Question 22

what are the 4 opportunities of cells that compartmentalise?

Answer 22

• Overcomes the problems associated with large volumes.
• Cells can change the number and type of organelles they produce in order to allow the cell to take on different functions.
• This allows cells to specialise.
• Different combinations of specialised cells creates the diversity of multicellular life on the planet.

Question 23

how many genes does a mycoplasma have?

Answer 23

~382 genes

Question 24

how many genes does a fruit fly have?

Answer 24

~17,000 genes

Question 25

how many genes does a chicken have?

Answer 25

~17,000 genes

Question 26

how many genes does a human have?

Answer 26

~22,000 genes

Question 27

how many genes does a tomato have?

Answer 27

~31,700 genes

Question 28

how many genes out of how many studied were found to be essential?

Answer 28

1,878 genes out of 18,166 genes studied are essential

Question 29

how much of our genome is essential for survival?

Answer 29

9.2%

Question 30

how many of the 18,166 genes studied do we not know the function of?

Answer 30

330