#1
Which part of the phospholipid is hydrophobic and hydrophilic?
Phosphate head = hydrophilic
Fatty acid tail = hydrophobic
How many hydrogen bonds between A and T? How many hydrogen bonds between C and G?
- Which enzyme can break these hydrogen bonds during DNA replication?
2 hydrogen bonds between A and T
3 hydrogen bonds between G and C
- Helicase.
Explain two reasons why this statement is false.
Both RNA polymerase and DNA polymerase need a primer made from DNA.
- Which enzyme makes the primer?
RNA polymerase does not need a primer.
DNA polymerase needs a primer made from RNA.
- Primase makes the primer.
A man has a diseased allele found on his X chromosome. He will pass this to all his daughter and son. True or false.
False. He will give the Y chromosome to his sons.
- All his daughters will have the diseased alelle.
If thymine makes up 30% of the nucleotide, adenine would make up?
30%
True or false. Phagocytosis and pinocytosis both require ATP.
True. Both phagocytosis and pinocytosis are types of endocytosis which is a form of active transport.
Fumarate is converted into malate by fumarase. Which molecule is the substrate? Which molecule has the active site?
- Fumarase (enzyme) = has the active site.
- Fumarate = substrate.
What is the similarity and difference between incomplete dominance and codominance?
Similarity:
- No alelle is dominant over the other.
Difference:
- Incomplete dominance = involves blending (ex. white and red flower breed to form pink flowers).
- Codominance = both alleles are expressed (ex. in blood type AB, both A and B antigens are present).
Glycoproteins are involved in cell-to-cell recognition and cell-to-cell communication. True or false.
True.
DNA polymerase reads the strand in the ______________ direction and synthesises in the _______________ direction.
Reads in the 3'>5' direction.
Synthesizes in the 5'>3' direction.
What is the probability that a child will be born with blood type B if the parents have blood types AB (genotype: AB), and B (genotype: BO)?
Probability of blood type A?
Probability of blood type AB?
Probability of blood type O?
Blood type B = 50%
Blood type A = 25%
Blood type AB = 25%
Blood type O = 0%.
What kind of molecules can freely move through cell membrane?
- What kind of molecules need proteins?
- Small, hydrophobic molecules and small, uncharged polar molecules.
- Molecules that need proteins include: large, uncharged polar molecules and ions.
What does it mean if the genetic code is degenerate?
What is polygenic inheritance? Give an example of a trait caused by polygenic inheritance.
Polygenic Inheritance = additive effect of two more genes on a single phenotype.
- Skin color in humans is an example
If the anticodon is GUC, what is the sense strand?
Anticodon = GUC (tRNA)
Codon = CAG (mRNA)
Antisense strand = GTC (template strand)
**Sense strand = CAG (complementary to template strand).
Pleiotropy = one gene influences two or more unrelated phenotypic traits.
- Example: Mutation in hemoglobin can cause sickle cell anemia > can lead to blindness and heart attack.
Cystic fibrosis is caused by a mutation in the CFTR gene. This leads to thick mucus. Explain how this occurs.
A mutation in CFTR gene leads to nonfunctional chloride channels > chloride ions cannot move out > sodium channels are not inhibited by CFTR so many sodium ions move in > concentration of chloride and sodium is higher in the cell so water does not move out by osmosis > mucus remains thick and sticky.
Translocation, inversion, and deletion are chromosomal mutations. What is translocation? What is inversion? What is deletion?
Translocation = One part of a chromosome moves to another nonhomologous chromosome.
Inversion = when a chromosome segment breaks off and reattaches within the same chromosome (but in reverse orientation).
Deletion = chromosome segment is lost.
What are the two types of genetic screening? What are the advantages and disadvantages of genetic screening?
Amniocentesis and chorionic villus sampling.
- Advantages = allows parents to prepare or terminate the pregnancy.
- Disadvantages = small risk of miscarriage and not always accurate.
During inhalation, what does the diaphragm and intercostal muscles (both internal and external) do? How does this affect volume and pressure?
Diaphragm contract and external intercostal contract (internal intercostal will relax) > increasing volume in the thorax > pressure (inversely proportional to volume) will decrease > since air pressure outside is greater than inside, air will flow in.
In which genetic screening test, is a sample of the placenta removed?
Chorionic villus sampling.
What factors can increase membrane fluidity? Give at least 3.
1. Increase in temperature
2. Increase in the proportion of unsaturated fatty acids = more space between phospholipids.
3. Decrease in cholesterol = so phospholipids do not pack together tightly.
4. Fatty acids with shorter side chains.
Why is it important for membranes to be fluid?
During temperature changes, membranes will undergo adjustments to maintain an optimal level of fluidity. Give two examples of changes membranes will undergo at high temperatures.
1. Increasing cholesterol content.
2. Converting unsaturated fatty acids to saturated ones.