Q what is the function of the mitochondria

1
Q what is the function of the mitochondria?

• A Site of respiration
• Providing the energy for the cell (life processes)

2
Q What happens before cell division takes place?

• A DNA copies itself

3
Q Describe the structure of DNA

• A
• A double helix two strands of bases attracted
  to each other by cross links between two bases

4
Q describe DNA replication

• A
• unzipping to form singe strands
• New double strands forming by complementary base
  pairing

5
Q Explain how protein structure is determined
by the DNA base code

• A A section of DNA (gene) codes for a protein
• - base sequence determines amino acid sequence
• - 3 bases code for one amino acid

6
Q What is transamination?

• A making an amino acid from another one.
• There are some amino acids we cannot make in this
  way, we call them essential amino acids because
  it is essential that we take them in in our diet
  to be healthy

7
Q State the stages in the production of a DNA
fingerprint

• A
• Isolation
• Fragmentation
• Separation
• Comparison with a reference

8
Q Explain how enzymes are complementary to
their substrate

• A The amino acid sequence makes the protein
  make a specific shape
• - the bit of the enzyme where a reaction takes
  place is called the active site
• - the substrate fits into the active site (lock
  and key)
• - the shape of the substrate is complementary to
  the shape of the active site

9
Q Explain how temperature affects the shape of
an enzyme

• A- As temperature gets too hot it causes the
  shape of the enzyme to change
• - the active site changes so the substrate
  cannot fit and a reaction cannot occur

10
Q Explain how pH affects the shape of an enzyme

• A- Each enzyme is adapted to work at a set pH
  range
• - as you move away from that range (higher or
  lower) the shape of the active site changes so
  that the substrate can no longer fit

11
Q Explain the term diffusion

• A -
• Net movement of particles
• From an area of high concentration to an area of
  low concentration
• Until an equilibrium is reached

12
Q Explain how you can increase the rate of
diffusion

• A
• Shorter distance (diffusion pathway)
• A greater concentration difference
• Greater surface area

13
Q What problem are there with heart
transplants?

• A Lack of donors
• - Tissue match
• - Size
• - Age
• - Rejection
• - Drug regime

14
Q Explain the advantages of being multi-cellular

• A
• Allows organisms to be larger
• Allows for cell differentiation
• Allows organisms to be more complex
• A single large cell has a smaller surface
  area/volume ratio reducing the movement of
  materials in and out of the cell

15
Q Explain what happens in mitosis

• A
• Chromosomes are copied to produce genetically
  identical cells
• Chromosomes divide to opposite poles of the cell
• Cell cleaves forming two genetically identical
  cells

16
Q Explain what happens in meiosis

• A
• Chromosome number is halved and genetically each
  cell is different
• Pairs of chromosomes separate to opposite poles
  of the cell in the first division
• Chromosomes divide to opposite poles of the cell
  in the second division

17
Q Explain how the sperm cell is adapted to its
function

• A
• Many mitochondria to provide energy
• Acrosome releases enzyme to digest the egg
  membrane

18
Q State the 3 structures found in plant cells
but not in animal cells

• A
• Cell wall
• Large vacuole
• Chloroplasts

19
Q Describe how plant and animal growth is
different

• A
• Animals tend to grow to a finite size but plants
  can grow continuously
• Cell enlargement is the main method by which
  plants gain height
• Cell division is mainly restricted to tips of
  shoots and roots
• Many plants retain the ability to differentiate
  but most animal cells loose the ability at an
  early stage

20
Q What is a stem cell

• A A cell that still has the ability to
  differentiate

21
Q Explain how geotropism affects roots

• A Auxin in root prevents cell elongation
• - gravity causes auxin to accumulate on lower
  side of root
• - cells at top elongate more than the bottom
  causing the root to curve downwards

22
Q Explain how geotropism affects shoots in the
dark

• A Auxin in shoot encourages cell elongation
• - gravity causes auxin to accumulate on lower
  side of shoot
• - cells at bottom, elongate more than the top
  causing the shoot to curve upwards

23
Q Explain what causes a shoot to bend towards
light

• A Auxin in the shoot encourages cell elongation
• - light causes auxin to accumulate on the dark
  side
• - more cell elongation on the dark side
• - shoot bends towards light

24
Q Explain selective breeding

• A
• Selection of characteristics
• Cross breeding
• Selection of suitable offspring over many
  generations (repeats of first two points)

25
Q What are the main problems with selective
breeding?

• A accumulation of harmful recessive
  characteristics
• - reduction in variation

26
Q Describe the principles of genetic engineering

• A
• Selection of characteristics
• Isolation of genes
• Insertion
• replication

27
Q give an advantage and disadvantage of genetic
engineering

• A Advantage production of organisms with
  desired features
• - Disadvantage inserted genes may have
  unexpected harmful effects

28
Q Describe in outline the cloning technique
used with embryo transplants in cows

• A
• Sperm collected from selected bulls
• Selected cows artificially inseminated
• Embryos collected
• Embryo split forming clones
• Embryo clones implanted into surrogate cows

29
Q Describe the advantages associated with the
commercial use of cloned plants

• A
• Can be sure of the characteristics of all plants
  as they are genetically identical
• It is possible to mass produce plants that may be
  difficult to grow from seed

30
Q Describe the disadvantages associated with
the commercial use of cloned plants

• A
• If plants are susceptible to disease or climate
  change all plants will die (genetically
  identical)
• Lack of genetic variation

31
Q Describe plant cloning by tissue culture

• A
• Selection for characteristics
• Large number of small pieces of tissue
• Aseptic technique
• Use of suitable growth medium and conditions

32
Q Explain why cloning plants is easier than
cloning animals

• A many plant cells retain the ability to
  differentiate, animal cells loose this at an
  early stage

33
Q Describe in outline the cloning technique
used to produce Dolly the sheep

• A
• Nucleus removed from an egg cell
• Egg cell nucleus replaced with the nucleus from
  an udder cell
• Cell implanted into another sheep
• Cell grows into a clone of the sheep from which
  the udder cell came