Y10 Spring Term Biology Roundup Flashcards
What is the digestive system?
An organ system in which organs work together to digest and absorb food
Name the organs in the digestive system (chronological order)
Mouth, Oesophagus, Liver, Stomach, Gallbladder, Pancreas, Small intestine, Large intestine and Anus
How do you test for:
1) Sugar (glucose)
2) Starch
3) Biuret
1) Benedict’s test - orange to brick red precipitate
2) Iodine test - turns black
3) Biuret reagent - mauve/purple solution
What are cells?
The basic building blocks of all living organisms
What are tissues?
A group of cells with a similar structure and function
What are organs?
Aggregations (working together) of tissues performing a specific function
What are organ systems?
Organs working together to form organ systems which work together to form an organism
What is the job of enzymes?
Enzymes catalyses (increase the rate of) specific reactions in living organisms
How do enzymes catalyse specific reactions?
Due to the shape of their active site
What is “the lock and key” theory?
A simplified model to explain enzymes in action
What factors affect the activity of enzymes?
Temperature and pH
What does every active enzyme have?
1) An optimum temperature
2) An optimum pH
What is meant by the term “a denatured enzyme”?
An enzyme that has changed shape so the substrate no longer fits the active site
What can cause an enzyme to become denatured?
- Temperature is too high
- pH is too high/low
What’s the job of digestive enzymes?
To speed up the conversation of large, insoluble molecules (food) into small, soluble molecules that can be absorbed into the bloodstream
Describe the function of amylase (carbohydrases)
- Made in the salivary glands, pancreas + small intestine
- Break down carbohydrates into simple sugar (eg. starch to glucose)
Describe the function of proteases?
- Made in the stomach + pancreas
- Break down proteins to amino acids
Describe the function of lipases?
- Made in the pancreas but works in the small intestine
- Break down lipids (fats) into glycerol and fatty acids
Describe the function of bile
- Made in the liver but stored in the gallbladder
- Emulsifies lipids to increase surface area to increase lipid breakdown by lipase. Changes pH to neutral for lipase to work
What are the epidermal tissues?
- Waxy cuticle (top layer of the leaf)
- Guard cells
- Stomata
Describe the job of the waxy cuticle?
Reduce water loss from the leaf
Describe the job of the guard cells/stomata?
Guard cells open/close the stomata to control water loss and allow gas exchange
Describe the job of the palisade mesophyll (palisade cells)?
Cells near the top surface of the leaf that are packed with chloroplasts that contain chlorophyll. Both adaptations maximise photosynthesis
Describe the job of the spongy mesophyll
- Air spaces in the leaf between the cells
- Increased surface area for gas exchange so that carbon dioxide can diffuse into photosynthesising cells
Describe the job of the xylem
- Hollow tubes strengthened by lignin adapted for the transportation of water in the transpiration system
- Allows transport of water and mineral ions from the roots to the stem and leaves
Describe the job of the phloem
- Cell sap moves from one phloem cell to the next through pores in the end walls
- Transports dissolved sugars from the leaves to the rest of the plant for immediate use/storage (translocation)
Describe the job of the meristem tissue
- New cells (roots and shoot tips) are made here including root hair cells
- Root hair cells have an increased surface area for the uptake of water by osmosis and mineral ions by active transport
State the cause, effect and treatment for faulty heart valves
- Cause: Valves don’t open/close properly
- Effect: Blood can leak/flow in the wrong direction
- Treatment: Biological valve transplant or a mechanical valve can be installed
State the cause, effect and treatment for coronary heart disease
- Cause: A build up of fatty substances in the coronary arteries (atherosclerosis)
- Effect: Oxygenated blood cannot get to the cardiac muscle
- Treatment: Stents —> inserted into the blocked artery to open it up. Statins —> lower harmful cholesterol
