Unit 1: Cells (Maybe)
Unit 2: Chemistry of Life (Probably)
Unit 3: Cellular Processes (Seems Legit)
Unit 4: Cells -> Organisms (Could be)
Unit 5: Animal Anatomy & Physiology (Chances look good)
100

Outline how the amphipathic properties of phospholipids help determine membrane structure. [4]

  1. membrane structure is double layer of phospholipids / bilayer;
  2. phospholipids consist of a phosphate head and 2 fatty acid tails;
  3. the (phosphate) head is polar / hydrophilic;
  4. the (fatty acid) tails are non-polar / hydrophobic;
  5. tails repel water/ are attracted to each other so found towards the inside (of the bilayer);
  6. head forms H bonds/ interacts with water so face outwards (of the bilayer)

-3 points, unless you can draw a 4 mark diagram of the cell membrane in one minute.  Then +10

100

Triglycerides are used as energy stores by living organisms. Describe their structure and properties. [4]

a.  made of carbon, hydrogen and oxygen
      OR
     are a group of lipids;
b.  (made of) one glycerol molecule and three fatty acids;
c.  formed by condensation reactions;
d.  fatty acids may be saturated or unsaturated;
e.  unsaturated fatty acids can be cis or trans (isomers);

Properties:
f.  hydrophobic/insoluble/not very soluble in water/soluble in non-polar solvents
      OR
    can be liquid or solid at room temperature;
g.  release/store large quantity of energy
       OR
     release/store more energy than carbohydrates (during cell respiration)/ OWTTE
       OR
     long term storage of energy;
h.  do not conduct heat well / heat insulators (as in fat layers/blubber);

Max [3] if only mention structure.

Accept labelled diagrams.


+16, unless Metal or Florencia is on your team.  Then you have to draw the structure of alpha glucose in one minute or 0 points

100

Explain the stages and processes of meiosis leading to genetic variation. [7]

  1. meiosis divides a diploid nucleus to produce (4) haploid nuclei;
  2. meiosis halves the chromosome number;
  3. chromosomes consist of two sister chromatids at the start of meiosis;
  4. homologous chromosomes are paired;
  5. crossing over occurs between homologous chromosomes;
  6. crossing over promotes genetic variation/new gene/allele combinations;
  7. pairs of homologous chromosomes are randomly oriented/assorted in the first division of meiosis
    OR
    sister chromatids are randomly assorted during the second division of meiosis;
  8. in the first division of meiosis pairs of homologous chromosomes are separated;
  9. random orientation promotes genetic variation/new gene/allele/chromosome combinations;
  10. meiosis produces haploid gametes (to ensure offspring have complete set of chromosomes);
  11. fusion of gametes from different parents promotes (genetic) variation;

Drawings which are annotated to explain are acceptable.


-5

100

Ask Ms. Burns a question from any other DP course.

If she got it right, +1

If she got it wrong, -5

100

Explain the roles of named hormones in the development and function of the sexual reproductive systems in males and females. [7]

  1. testosterone causes (pre-natal) development of male genitalia;
  2. testosterone controls the development of male secondary sexual characteristics (during puberty/adolescence);
  3. testosterone controls sperm production;
  4. estrogen and progesterone cause (pre-natal) development of female reproductive organs;
  5. estrogen (and progesterone) controls the development of female secondary sexual characteristics (during puberty/adolescence);
  6. follicle stimulating hormone/FSH stimulates the growth of follicle in ovaries / FSH stimulates production of sperm (in men);
  7. FSH stimulates estrogen secretion (from developing follicles);
  8. luteinizing hormone/LH causes ovulation/formation of corpus luteum;
  9. thus LH stimulates estrogen/progesterone secretion (from corpus luteum) / LH stimulates testosterone (in men);
  10. estrogen builds/thickens/repairs uterine lining/endometrium;
  11. estrogen inhibits FSH (by negative feedback)
    OR
    estrogen stimulates LH (release) (by positive feedback);
  12. progesterone inhibits FSH and LH;
  13. progesterone thickens/maintains thick uterine lining/endometrium;
  14. hCG/human chorionic gonadotrophin stimulates the production of progesterone during pregnancy;

Max 2 per hormone.

Must include testosterone for full marks.


+1

200

Which statement distinguishes between the roles of free and bound ribosomes?

A.  Free ribosomes synthesize proteins for use inside the cell, whereas bound ribosomes synthesize proteins mainly for export.

B.  Free ribosomes synthesize proteins mainly for export, whereas bound ribosomes synthesize proteins for use inside the cell.

C.  Free ribosomes synthesize proteins, whereas bound ribosomes do not.

D.  Bound ribosomes synthesize proteins, whereas free ribosomes do not.

A.  Free ribosomes synthesize proteins for use inside the cell, whereas bound ribosomes synthesize proteins mainly for export.


+6

200

Describe the structure of cellulose molecules. [3]

Markscheme

  1. beta/β glucose (subunits/monomers in cellulose) / diagram showing position of OH groups in beta glucose molecule;
  2. C1 to C4 bonds / glycosidic bonds (between glucose molecules);
  3. unbranched/linear (polymer/molecule/chain);
  4. straight/not helical (polymer/molecule/chain);
  5. glucose subunits orientated alternately upwards and downwards/OWTTE;
  6. hydrogen bonding between adjacent cellulose molecules/polymers;

+7 if you a person from your team can hold a plank for one minute

200

Outline the processes occurring during interphase in the cell cycle. [4]

  1. growth/increase in cell size;
  2. division of mitochondria/chloroplasts/production of more organelles/number of organelles doubled;
  3. replication of DNA/amount of DNA is doubled;
  4. transcription of genes/production of mRNA;
  5. protein synthesis;
  6. cell respiration/production of ATP;


-5 unless someone on your team can draw the cell cycle in one minute. Then no points lost

200

Outline how stem cells develop into specialized cells during development of the embryo. [2]

  1. (by a process called) cell differentiation;
  2. different genes are expressed/ switched on;
  3. different concentrations of signaling molecules/ molecules determine position of cells in embryo;

-5

200

Describe how non-disjunction can cause Down syndrome. [4]

  1. Down’s syndrome is due to an extra chromosome (21) / trisomy 21;
  2. occurs in meiosis;
  3. during anaphase (I or II);
  4. homologous chromosomes (21) fail to separate (in anaphase I)
    OR
    chromatids (21) fail to separate (in anaphase II);
  5. leads to a gamete/zygote with one extra chromosome (21);
  6. (mainly) occurs in ovaries;
  7. in the formation of egg cells/ova/gametes;
  8. probability of nondisjunction increases with paternal/maternal age;

Mpe. Requires reference to gamete or zygote.

+5

300

Why do onions make you cry?

a) They're emotionally manipulative
b) They release sulfur compounds that irritate your eyes
c) They're jealous of garlic’s popularity
d) It's their defense mechanism against chefs

a) They're emotionally manipulative

Technically they release sulfur compounds, but a) is the better answer


+19 if you picked a)

+1 if you picked b)


300

What is the best science?

Biology. Obviously.


+10 if you got this right

-20 if you got this wrong

300

What percentage of DNA do bananas and humans share? (closest % wins the question)

Approximately 60%

+20

300

Describe the role of two named hormones in the regulation of blood sugar levels. [4]

a.  Insulin and glucagon released (from the pancreas to regulate blood glucose
     levels);
b.  blood glucose levels are regulated by negative feedback;

At least 1 of these:
c.  when blood glucose levels are above normal, insulin is released from the β/beta-
     cells of the pancreas;
d.  insulin stimulates cells to take up glucose;

At least 1 of these:
e.  when blood glucose levels are below normal, glucagon is released from the
     α/alpha-cells of the pancreas;
f.  glucagon stimulates the release of glucose, from glycogen stored in the liver;

a. It is sufficient to say the hormones are insulin and glucagon.

For maximum marks students must give marking point c or d and marking point e or f.

Accept labelled table or diagram.


Either +10 or trade points with the other team

300

+10 points if you get your team to guess five vocabulary words in one minute

Alveoli

Antibody

Negative Feedback Loop

Pulmonary Vein

Platelets

400

Describe how substances cross the cell membrane by facilitated diffusion. [4]

  1. (in facilitated diffusion), molecules diffuse from areas of high to low concentration/down the concentration gradient;
  2. membrane interior is mostly hydrophobic;
  3. (facilitated diffusion) allows polar molecules to cross a membrane;
  4. with the assistance of channel/membrane proteins;
  5. transport/integral proteins span the width of the membrane;
  6. (this protein is) a hydrophilic channel that allows substances to diffuse through;
  7. energy/ATP is not used in this process/passive transport;


+1

400
Draw a labelled diagram to show the structure of a single nucleotide of RNA. [3]
  1. ribose drawn as a pentagon and labelled;
  2. base linked correctly (to C1) of ribose and labelled;
  3. phosphate linked correctly (to C4) of ribose and labelled;

-4

400

Explain the role of RNA in translation, resulting in the formation of polypeptide chains. [7]

  1. RNA allows the DNA/genetic code to be expressed as a polypeptide;
  2. (translation) involves both messenger RNA/mRNA and transfer RNA/tRNA;
  3. mRNA nucleotide sequence determines the amino acid sequence of the polypeptide;
  4. mRNA binds to a ribosome;
  5. (mRNA) has triplets of bases / 3 bases known as codons;
  6. each tRNA has a triplet of bases called an anticodon;
  7. specific amino acid attached to tRNA (depending on anticodon);
  8. tRNA binds to the mRNA/codon;
  9. (tRNA binds to mRNA) following rules of complementary base pairing; OWTTE
  10. tRNA adds its amino acid to the polypeptide chain;


-5

400

Outline the process of saltatory conduction. [2]

  1. gaps in myelin sheath (called nodes of Ranvier);
  2. depolarization jumps from gap to gap/node to node;
  3. speeds up the nerve transmission
    OR
    allows nerve impulse to move rapidly over long distances;


+5

400

Explain how cells in the bloodstream cause a specific immune response. [7]

  1. (specific immune response is) production of antibodies in response to a particular pathogen;
  2. antibody is specific to/binds to a specific antigen;
  3. macrophages/phagocytes engulf/present antigens from pathogens/viruses/bacteria;
  4. T lymphocytes activated by antigens/antigen presentation/antigens presented by macrophage;
  5. (activated) T lymphocytes activate B lymphocytes;
  6. only B lymphocytes that produce antibodies against the antigen/pathogen are activated;
  7. (activated) B lymphocytes clone/divide by mitosis to form plasma cells;
  8. plasma cells then secrete (large quantity) of an antibody/secrete antibodies of same type;
  9. some B lymphocytes/plasma cells form memory cells;
  10. memory cells give long-lasting immunity/faster response to a disease/pathogen;


+20

500

What distinguishes simple diffusion from facilitated diffusion?

A.  Simple diffusion occurs in both prokaryotes and eukaryotes, while facilitated diffusion only occurs in eukaryotes.

B.  Energy is not required for simple diffusion, while facilitated diffusion requires ATP.

C.  The rate of facilitated diffusion depends on the number of transport proteins in the membrane, while simple diffusion does not.

D.  Simple diffusion can only move substances along the concentration gradient, while facilitated diffusion can move substances along or against the concentration gradient.

C.  The rate of facilitated diffusion depends on the number of transport proteins in the membrane, while simple diffusion does not.


-5 points

500

Outline protein structure. [4]

Amino Acid structure [1 mark max]

Contains an amine group

Contains a COOH

R group

Protein composition:
a.  (proteins) are made of (20) amino acids;

Primary structure:
b.  amino acids are linked by peptide bonds;
c.  joined by condensation;
d.  joined/linked into polypeptides;

Secondary and tertiary structure:
e.  interactions between/sequence amino acids lead to the 3-dimensional
     conformation/shape of proteins;

Quaternary structure:
f.  (some) proteins many consist of more than one polypeptide/amino acid chain
    linked together;


-5

500

Outline the reason that DNA replication is described as semi-conservative. [3]

  1. replication is forming new DNA/strands from existing DNA/strands;
  2. nucleotides added to exposed bases/to exposed strand/to bases on the template strand;
  3. complementary base pairing (between free nucleotides and template/existing strands);
  4. both strands/lagging and leading strands of the (parent) DNA act as templates/OWTTE;
  5. one newly synthesized strand and one original/conserved strand (in daughter molecules);


+3 for your team

-2 for every other team

500

Describe what occurs in a neuron when an action potential is propagated along the axon. [4]

  1. odium ions/Na+ enter/diffuse in;
  2. depolarization/membrane potential/voltage changes from negative to positive;
  3. potassium channels open AND potassium ions/K+ exit/diffuse out;
  4. repolarization/membrane potential/voltage changes back from positive to negative;
  5. local current due to diffusion of sodium ions along the neuron;
  6. (local currents) cause next sodium channels to open/next part of axon to depolarize;
  7. opening of sodium channels triggered when threshold potential/-50mV reached;

+10

500

Distinguish between the structure of arteries and veins. [2]

  1. thick wall/muscle of artery versus thin wall/muscle of vein;
  2. (much) more elastic tissue in artery than in vein;
  3. small lumen of artery vs large lumen in vein;
  4. veins have valves, arteries do not;

+8, unless you are the tallest team in the room, then -3

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