Organisation And Digestion Flashcards
What is a tissue?
A group of cells with a similar structure and function
Define and describe an organ.
Organs are collections of tissues performing specific functions. Organs are organised in organ systems, which work together to form organisms
What are carbohydrates made up of?
Units of sugar.
How do enzymes work?
The substrate binds to the active site and the reaction is catalysed by the enzyme
Can enzymes be killed?
Enzymes aren’t killed, they are molecules, not living things themselves. They can be denatured
How are enzymes denatured?
High temperatures denatured the enzyme, changing the shape of the active site so it can no longer bind to the substrate.
pH can affect the shape of the active site of an enzyme and make it work very efficiently or stop it working.
What is digestion?
Digestion is the breakdown of large insoluble molecules into soluble substances that can be absorbed into the blood across the wall of the small intestine.
Where are digestive enzymes produced?
Digestive enzymes are produced by specialised cells in glands in the lining of the digestive system.
What are enzymes that break down carbohydrates called?
Carbohydrases
Which enzyme breaks down starch?
Amylase that is produced in the salivary glands
What enzymes break down proteins such as meat, fish ,and cheese?
Proteases which are produced in the stomach, pancreas, and small intestine.
Proteases break down proteins into amino acids
What enzyme breaks down fats?
Lipase is produced in the small intestine and pancreas, and breaks down fats and lipids into fatty acids and glycerol.
Using pH, how does the body make digestion as efficient as possible?
-the protease enzymes of the stomach work best in acid conditions, the stomach produces hydrochloric acid, which maintains a low pH.
-the enzymes made in the pancreas and the small intestine work best in alkaline conditions, bile produced in the liver, stored in the gall bladder, and released through the bile duct neutralised acid and emulsifies fats.
What is the human circulatory systems main function? (1 mark)
The blood, blood vessels, and heart make up the circulatory system which transports substances to and from the body cells.
What are platelets?
Cell fragments that start the clotting process at wound sites
What do white blood cells do?
White blood cells help to protect the body against infection.
What do red blood cells contain that binds to oxygen?
Haemoglobin that binds to oxygen to transport it from the lungs to the tissues
What is plasma’s function?
Plasma has blood cells suspended in it and transports proteins and other chemicals around the body.
Where do substances dissolve into and out of the blood in the human circulatory system?
In the capillaries
How is an artery specialised for its function?
Arteries have thick walls containing muscle and elastic fibres.
Arteries have a small lumen
How is an artery specialised for its function?
Arteries have thick walls containing muscle and elastic fibres.
Arteries have a small lumen
How is a vein specialised for its function?
Valves that open as the blood flows through them toward the heart to prevent backflow
How is a capillary specialised for its function?
Thin walls that are only a single cell thick make diffusion quicker
How can stents be used in the circulatory system?
To keep narrowed or blocked arteries open
How can stents be used in the circulatory system
to keep narrowed or blocked arteries open
What do statins do?
Reduce cholesterol levels in the blood, reducing the risk of coronary disease
What is the resting heart rate of a human controlled by?
A group of cells in the right atrium that form a natural pacemaker
What are artificial pacemakers used for?
To correct irregularities in the heart rhythm
How are the alveoli specialised for their function?
A large surface area
Rich blood supply
Very thin alveolus walls
Ventilation- steep diffusion gradient
What allow gases to move into and out of the leaf?
Stomata
What is a vascular bundle?
Both the xylem and phloem
What does the phloem do?
Transports dissolved sugars from the leaves up and down the plant
What do the xylem cells do?
Transports water and mineral ions up the plant from the roots to the leaves and stem
How are the cells in the spongy metaphyll area of the plant specialised?
The cells have large surface areas for gas exchange
What is the loss of water vapour from the surface of plant leaves known as?
Transpiration
Water is lost through where in a leaf?
Stomata, which open to let in carbon dioxide for photosynthesis
The stomata and guard cells control what?
Gas exchange and water loss
Factor that increase the rate of photosynthesis or increase stomatal opening will increase the rate of……
Transpiration
What factors affect the rate of transpiration?
Temperature
Humidity
Air flow
Light intensity
What conditions is transpiration more rapid in?
Hot, dry, windy, or bright conditions
