A-Level Biology Paper 1: General Exam Flashcards

• B. This is because it cannot be:

• A, as macromolecules formed via condensation reactions

• C, as lipids don’t form polymers

• D, as lipids are macromolecules but aren’t composed of repeating units.
  

• A. This is because extrinsic proteins are embedded within the bilayer. it cannot be:

• B, as glycolipids are not proteins

• C, as the bilayer is fluid, not rigid.

• D, as the bilayer is semi-permeable.

• B. This is because invertebrates undergo mechanical ventilation, as muscular contractions of the abdomen allow for air to be forced in and out of the tracheal system, maintains a steep concentration gradient. it cannot be:

• A, which decreases volume of tracheal fluid

• C, as spiracles lead to tracheae then tracheoles

• D, as spiracles are capable of opening and closing, not tracheoles

• D. This is because E represents the sinusoid, in which blood containing substances absorbed from the digestive system flow through it, and the hepatocytes lining the cell absorb these toxic substances. It cannot be:

• A, as blood flows through the periphery to the central vein, the statement implies otherwise

• B, as the hepatic portal vein carries blood arriving from the digestive system. H is the branch of the hepatic artery

• C, as F represents the bile duct, and hepatocytes produce bile, which is released into the blood to be carried to the kidney.

• B. The large circular white space on the right side of the image is a Central Vein (center of a lobule).

• The structure labelled J is located in the connective tissue between lobules (the portal tract/triad).

• The vessel at J has a large, irregular lumen and a thin wall, which distinguishes it as a vein rather than an artery (which would be smaller with a thick muscular wall).

• Therefore, J is a branch of the Hepatic portal vein.

• A. This is accounted for by: Statement 1 → Low light intensity leads to the LDR slowing down, so less ATP, less NAPDH

• Statement 2 → High light intensity, LDR produces more ATP + NAPDH, regeneration of RuBP from TP requiring ATP.

• Statement 3 → High light intensity, light not the limiting factor; changes to CO₂ or temperature, if CO₂, slows rate of RuBP conversion to GP, and RuBP regenerated faster than it is accumulated.

• C. This is because lipids have significantly higher energy values than proteins. it cannot be:

• A, as it has less C-H due to the presence of the OH’s

• B, as due to the lipid content, chocolate has a higher energy value

• D, as carbohydrates have higher energy value.

• a) Water

• Carbon Dioxide

• Oxygen

1. b) Respiration provides water and carbon dioxide, which is used as reactants for photosynthesis

2. Photosynthesis provides glucose and oxygen which is needed for respiration

3. Water used for photolysis

4. CO₂ used for the Calvin Cycle

ii) Explain why the percentage of light used in photosynthesis is higher than your answer to part (i) at wavelengths other than 680 nm.

iii) Porphyra naiadum grows in deep water. Use the data in Fig. 17.2 to suggest how it is able to survive in conditions where other types of algae or plant cannot.

 i) 24%

ii) Due to the presence of accessory pigments, which absorb different wavelengths of light for use in the LDR.

iii) Algae have pigments that can absorb shorter wavelengths of light, and these wavelengths can penetrate water at greater depths.

iii) Furosemide is a banned substance because it can be used as a masking agent, to hide the use of performance enhancing drugs. Suggest how furosemide could act as a masking agent.

i) Cannabis

ii) Causes rapid water loss, causing a larger volume of urine to be produced.

iii) By increasing urine volume, it dilutes the concentration of other banned substances in the urine.

What is the formula for net pressure?

Formula: Net Pressure = (Net Hydrostatic Pressure) + (Net Oncotic Pressure)

Describe the events taking place at the points marked W, X, Y and Z and explain how these events are related to the changes in pressure shown in the diagram.