b2

• Features of all cells

  Nucleus

  Cytoplasm

  Cell membrane

  Mitochondria

  Ribosomes
• Features of only plant/algae cells

  Cell wall (made of cellulose)

  Chloroplasts (containing chlorophyll)

  Permanent vacuole
• Features of bacterial cells

  No nucleus - genetic material free in cytoplasm

  Cytoplasm

  Plasmids

  Cell membrane

  Cell wall

  Slime capsule

  Flagella
• Features of yeast cells

  Nucleus

  Cytoplasm

  Cell membrane

  Cell wall (containing NO CELLULOSE)
• Function of nucleus

  Controls cell's activities
• Function of cytoplasm

  Where most chemical reactions take place
• Function of cell membrane

  Controls what enters and leaves the cell
• Function of mitochondria

  Carry out respiration to release energy
• Function of ribosomes

  Protein synthesis
• Function of cell wall

  Rigid - provides support, helping plant stand up
• Function of chloroplasts

  Carry out photosynthesis with light energy absorbed by the chlorophyll
• Process of diffusion

  Molecules in fluids have lots of energy

  Move around randomly

  Molecules spread out

  Net movement from area of high concentration to area of low concentration
• 3 types of animal tissue and their roles

  Muscular - contracts to bring about movement

  Glandular - produces substances like enzymes and hormones

  Epithelial - covers some areas of the body
• 4 types of plant tissue and their roles

  Epidermal - covers the plant

  Mesophyll - contains chloloplasts for photosynthesis

  Xylem - transports water and mineral ions around plant

  Phloem - transports sugars around plant
• Description of how the 3 animal tissues work together

  In the stomach:

  Muscular tissue churns stomach contents

  Glandular tissues produce digestive juices

  Epithelial tissue covers outside and inside of organ
• Organs involved in digestive system with their function

  Salivary glands - produce digestive juices to help break down food molecules

  Stomach - churns food, mixing it with digestive juices, breaks it down and kills pathogens with hydrochloric acid

  Liver - produces bile to create alkaline conditions in small intestine

  Small intestine - absorbs soluble food molecules

  Large intestine - absorbs water
• Photosynthesis word equation

  Carbon dioxide + water _>_ glucose + oxygen

  Light energy used to convert reactants
• How to test for starch

  Iodine solution on leaf - areas with starch turn blue/black (areas without are yellow/brown) proving that photosynthesis has taken place.
• Limiting factors for photosynthesis

  -temperature

  -level of CO2

  -level of light

  -level of water
• Uses for glucose plants

  - converted into starch for storage

  - converted into fats & oils for storage

  - used in respiration to release energy

  - used to produce cellulose to strengthen cell wall

  - produces proteins (also need mineral ions)
• Physical factors that affect distribution of organisms

  Availability of:

  - water

  - nutrients

  - light

  - oxygen

  - carbon dioxide.

  Also,

  - temperature.
• Definition of valid

  All variables are controlled, ensuring that only the independent variable is affecting the result.
• Definition of repeatable

  Same investigator using same method obtains same results
• Definition of reproducible

  Different investigator AND/OR different method obtains same results.
• Protein molecules are made up of...

  Long chains of amino acids
• Roles of proteins

  - as structural components of tissues, e.g. muscle

  - as hormones

  - as antibodies

  - as catalysts
• Enzymes are...

  Biological catalysts that control and speed up chemical reactions in cells.

  They are large protein molecules.

  They have an active site which is exactly complementary to its substrate.
• Enzymes can...

  - build larger molecules from smaller ones, e.g. proteins from amino acids

  - break larger molecules down into smaller ones, e.g. food molecules to make digestion more efficient

  - change one molecule into another one, e.g. converting sugar types
• Enzyme action is affected by...

  Temperature: too slow = too slow, too high = denature and don't work.

  pH value: wrong = denature and don't work.
• 3 different types of digestive enzymes

  Amylase, protease and lipase
• Role of amylase

  Catalyses digestion of starch into sugars
• Where amylase is produced

  Salivary glands, pancreas and small intestine
• Where amylase works

  Mouth and small intestine
• Conditions amylase likes


  Slightly alkaline
• Role of protease

  Catalyses breakdown of proteins into amino acids
• Where protease is produced

  Stomach, pancreas and small intestine
• Where protease works

  Stomach and small intestine
• Conditions protease likes

  Acidic
• Role of lipase

  To catalyze breakdown of fats (lipids) into fatty acids and glycerol
• Where lipase is produced

  Pancreas and small intestine