Unit 1 Essentials Flashcards
What part of the phospholipid is hydrophobic?
The tail. It points inside the bilayer
What is a phospholipid made up of?
2 fatty acid chains (lipids) and a phosphate molecule
What part of the phospholipid is hydrophilic?
The head. It points outwards in the water.
Name the type of reaction that joins monosaccharides together.
A condensation reaction.
What does the rough endoplasmic reticulum do?
It has ribosomes that make proteins.
How is the Golgi apparatus involved in the production of enzymes?
It modifies proteins and packages them into vesicles ready to be sent to the cell surface.
Why do enzymes catalyse only one type of reaction?
Enzyme has a specific active site and only one type of substrate fits it.
Describe two adaptions of the structure of alveoli for efficient gas exchange
Thin walls to reduce diffusion pathway. Total surface area is large.
People who have been fire-breathers for many years often find they cannot breathe out properly. Explain why.
Loss of elastic tissue. Scarred tissue. Less recoil. This is fibrosis.
How can cholera cause diarrhoea?
Toxin produced by the bacterium causes chloride ions to move into the lumen of the intestine. Water potential in the cells of the intestine decreases and so water moves by osmosis into the lumen.
In areas where there are repeated outbreaks of cholera, most people who become infected by cholera bacteria do not become ill. Suggest and explain one reason why.
These people have produced memory cells after a previous vaccination or infection.
Why is the process of active transport usually faster above 37 degrees?
Because of faster respiration and ATP production.
Describe how you would test a food sample for starch.
Add iodine to the food sample. If it turns black, starch is present.
The concentration of glucose in the blood rises after eating a meal containing carbohydrates. The rise is slower if the carbohydrate is starch rather than sucrose. Explain why.
Starch is digested to maltose by amylase. Maltose is digested to glucose by Maltase. Digestion of sucrose is a single step, there’s only one enzyme involved.
Describe how a heartbeat is initiated and coordinated.
SAN sends a wave of electrical impulses across the atria, causing atrial contraction. Non-conducting tissue prevents the impulses from reaching the ventricles. AVN waits for the blood to fill the ventricles. Then the AVN sends impulses to the bundle of His, causing the ventricles to contract.
Explain how the heart muscle and the heart valves maintain a one-way flow of blood from the left atrium to the aorta.
Atrium has higher pressure than ventricle so the atrioventricular valve opens. The ventricle has higher pressure than atrium so the atrioventricular valves close, ventricle has higher pressure than aorta so the semilunar valves open. Higher pressure in the aorta than ventricle so semilunar valve closes. Muscle contraction causes increase in pressure.
How can you calculate pulmonary ventilation?
Pulmonary ventilation = Tidal volume x Ventilation rate
What is the function of a mitochondrion?
To do aerobic respiration.
Why can’t the organelles in a cell be seen with a light microscope?
Because the resolution is not great enough to distinguish between two objects of that size because light’s wavelength is too long.
Name the constituent monosaccharides of the disaccharide sucrose.
Glucose and fructose.
Name the constituent monosaccharides of the disaccharide lactose.
Glucose and galactose.
Where is amylase produced and what is the product of the reaction it catalyses?
In the pancreas/salivary glands. Starch into maltose.
Where is maltase produced and what is the product of the reaction it catalyses?
In epithelium of the small intestine. Maltose into glucose.
How does the addition of a phosphate group to a non-functional form of an enzyme lead to the production of the functional form of that enzyme?
Phosphate changes the shape the enzyme’s active site. The active site is then complementary to the substrate and can form a substrate-enzyme complex.
Why does the left ventricle require more contraction power than the right ventricle?
Because it needs to pump blood further all the way around the body, it produces a greater pressure.
Suggest why the pulse felt can be used to measure heart rate.
The pulse is caused by pressure of blood from one contraction of the left ventricle.
What are the processes in which substances cross the cell-surface membrane.
Osmosis, facilitated diffusion, active transport, phagocytosis/endocytosis, exocytosis.
What is the process of osmosis?
Water molecules moving from a high water potential to a lower water potential through water channels.
What is the process of facilitated diffusion?
Where molecules are transported through a carrier protein down a concentration gradient.
What is active transport?
Where molecules are transported through a carrier protein against the concentration gradient using ATP from respiration.
What is phagocytosis?
Engulfing by cell surface membrane to form vacuole.
What is exocytosis?
Fusion of vesicle with cell surface membrane.
