2016 Unit 1 Flashcards
Give one piece of evidence that supports the theory that mitochondria evolved from prokaryotic cells.
- Circular DNA /
- Smaller
- No introns /
- No histones/proteins associated with DNA
What is the advantage to cells of having mitochondria?
• Able to respire aerobically
• So make (more) ATP/ release (more)
energy
Explain how the highest blood pressure is produced in the left ventricle.
• Stronger contractions
Some babies are born with a hole between the right and the left ventricles.
These babies are unable to get enough oxygen to their tissues.
Suggest why.
• Blood flows from left ventricle to right
ventricle/ mixing of oxygenated and deoxygenated blood;
• Lower volume of (oxygenated) blood
leaves left ventricle/flows into aorta/
• Less oxygen in blood leaving left
ventricle/aorta/
Explain why the pH decreases when the lipase is added to the milk.
• Fatty acids produced
Name the part of a pancreatic cell that produces the inactive form of trypsin.
• Ribosome/rough endoplasmic reticulum
Suggest the advantage of producing trypsin in an inactive form inside cells in the
pancreas.
• Does not digest protein inside cells;
• So (pancreatic) cell/tissue/function not
destroyed/damaged
•
Name the type of bond hydrolysed when the short chain of amino acids is removed.
• Peptide bonds
Explain how the competitive inhibitor stops trypsin working.
• Inhibitor is a similar shape to the substrate • (Inhibitor) blocks active site/is complementary to the active site/binds to the active site (of trypsin); • Fewer ES complexes formed
Explain the role of the diaphragm in breathing out.
• Diaphragm moves up /becomes dome shaped • Reduces volume of thorax / increase pressure in thorax • Pressure in thorax higher than outside (air)
People who do not have the specific receptor protein in their cell-surface membranes
may be infected with the Ebola virus but do not develop the disease. Explain why they do not develop the disease.
• Virus can’t bind (to receptor)/ can’t enter cells • So can’t be replicated/ • So, doesn’t damage cell(s)/tissues (and cause symptoms)
Explain the increase in specific plasma cells and antibody in people infected with the
Ebola virus.
• Antigen/glycoprotein on Ebola binds to/stimulates (a specific) B cell • (Binding causes) replication/cloning of B cell • Plasma cells/B cells release/produce antibodies
Explain how a blood transfusion from a patient recently recovered from Ebola may be an
effective treatment
• Lots of antibodies (against Ebola) in recovered patient • Transfusion/plasma contains antibodies • Antibodies (specific so) will bind with (Ebola) antigen • (In recipient) virus destroyed/cannot enter cell
A high mutation rate makes it difficult to develop a vaccine.
Explain why
• (High mutation rate leads to) antigens change/antigenic variability • Vaccine contains specific antigen; • Antibodies not complementary to (changed) antigen / won’t bind to (changed) antigens
Glucose is absorbed from the lumen of the small intestine into epithelial cells.
Explain how the transport of sodium ions is involved in the absorption of glucose by
epithelial cells
• Na+ ions leave epithelial cell and enter blood • (Transport out is by) active transport / pump / via carrier protein using ATP • So, Na+ conc. in cell is lower than in lumen (of gut) • Sodium/Na+ ions enter by facilitated diffusion; • Glucose absorbed with Na+ ions against their concentration/diffusion gradient / glucose absorbed down an electrochemical gradient;
