2013 Unit 1 Flashcards
Name the type of reaction that joins monosaccharides together
• Condensation Reaction
Some cells lining the bronchi of the lungs secrete large amounts of mucus. Mucus
contains protein.
Name one organelle that you would expect to find in large numbers in a
mucus-secreting cell and describe its role in the production of mucus
Golgi Apparatus • Package/process proteins RER/Ribosomes • Make polypeptides/proteins/forming peptide bonds Mitochondria • Releases energy/makes ATP Vesicles • Secretion/transport of proteins
An enzyme catalyses only one reaction. Explain why
- Enzymes have an active site
* Only substrate fits the active site
Name the process by which oxygen passes from an alveolus in the lungs into the
blood.
• Simple diffusion
Describe two adaptations of the structure of alveoli for efficient gas exchange.
- Thin walls/cells so a shorter diffusion pathway
* Surface area is large
Fire-breathers do this by
blowing a fine mist of paraffin oil onto a flame. Some of this mist can be inhaled and
may eventually lead to fibrosis.
People who have been fire-breathers for many years often find they cannot breathe out
properly. Explain why.
- Loss of elasticity/elastic tissue
- Scar tissue
- Less recoil
Infection by the cholera bacterium can cause acute diarrhoea. Explain how
- Toxin( produced by bacterium) cause chloride ions to move into lumen of intestine
- Water potential (of intestine contents) falls/ water moves by osmosis into intestine
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.
• Have produced memory cells -After previous infection/vaccination • Different forms of cholera -Some don't produce much toxins • Some people naturally resistant to bacterium - Because of cell structure
Describe how you would test a sample of food for the presence of starch.
- Iodine/potassium iodide solution to the food sample
* Blue/Black indicates 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 digested to maltose/by amylase
- Maltose digested to glucose/by maltase
- Digestion of sucrose is a single step/only one enzyme/sucrase
Give two adaptations that other epithelial cells have for the absorption of food.
- Microvilli
- Carrier proteins/ Co-transport proteins/membrane-bound organelles
- Many mitochondria
What is an antigen?
• A substance that causes an immune response/ production of antibodies
Antigens are not able to pass through the cell-surface membranes of other epithelial cells. Suggest two reasons why.
- Not lipid soluble
- Too large to diffuse through membrane
- Antigens do not have complementary shape/ cannot bind to receptor/channel/carrier proteins (in membranes of epithelial cells)
Scientists believe that it may be possible to develop vaccines that make use of
microfold cells (lines 9 -10).
Explain how this sort of vaccine would lead to a person
developing immunity to a pathogen.
- Vaccines contain antigen/attenuated/dead pathogens
- Microfold bind and present transport antigen (to immune system)
- T-cells activate B-cells
- B-cells divide/form clone/undergo mitosis
- B-cells produce antibodies
- Memory cells are produced
- More antibodies produced faster in secondary response
Describe how a heartbeat is initiated and coordinated.
- SAN sends wave of electrical activity/impulses across atria causing atrial contraction
- Non-conducting tissues prevents immediate contraction of ventricles/ prevents impulses reaching the ventricles
- AVN delays impulse whilst blood leaves atria/ventricles fill
- AVN sends wave of electrical activity
- Causing ventricles to contract from base up
