B2 Organisation Combined Science Flashcards
What is a tissue?
A group of specialised cells that work together.
What is an organ?
A group of tissues working together.
What is an enzyme?
A biological catalyst (a protein that speeds up reactions in the body).
What enzyme breaks down starch?
Amylase
What enzyme breaks down proteins?
Protease
What enzyme breaks down fats?
Lipase
What are the 2 functions of bile?
Emulsifies fats, neutralises stomach acid.
What are the products of digestion of starch?
glucose
What are the products of digestion of protein?
amino acids
What are the products of digestion of fats?
fatty acids and glycerol
Why are enzymes so specific?
The shape of their active site matches the shape of their substrate (lock and key model).
What 2 factors cause the active site of an enzyme to change shape?
Temperature increase, pH increase OR decrease.
What happens to an enzyme at high temperatures?
It denatures (active site changes shape).
What is the test for starch?
iodine turns blue/black
What is the test for sugars?
benedicts (heated) turns orange
What is the test for protein?
biurets turns purple
What is the test for fats?
Sudan III - you see a red layer
What are the 4 components of the blood?
red blood cells, white blood cells, plasma, platelets.
Name the upper and lower chambers of the heart.
Upper ? Atria, Lower ? ventricles
What are the adaptations of capillaries?
1 cell thick
What are the adaptations of arteries?
elastic walls
What are the adaptations of veins?
valves to prevent back flow
What are the structures in the lungs where the actual gas exchange happens?
Alveoli
How is oxygen transported in the blood?
In red blood cells attached to haemoglobin.
What is a) on this leaf diagram and give the function of this tissue.
a) epidermis. Has waxy cuticle to prevent water loss
What is b) on this leaf diagram and give the function of this tissue.
b) palisade. has chloroplasts for photosynthesis
What is c) on this leaf diagram and give the function of this tissue.
c) Xylem. Dead cells no ends for transport of water (transpiration). And Phloem. Hollow cells with holes in ends transport of dissolved sugars etc.(translocation).
What is d) on this leaf diagram and give the function of this tissue.
d) guard cells. controls the opening and closing of the stomata
What is e) on this leaf diagram and give the function of this tissue.
e) stomata. hole in bottom of leaf for gases and water to pass in and out.
What is f) on this leaf diagram and give the function of this tissue.
spongy mesophyll layer. lots of gaps for gases to pass though.
