Biology chapter 2 - cell systems

Pancreas

Pancreas

Creates enzymes for digestion.

Liver

Produces bile for fat digestion.

Gall bladder

Stores bile until needed for digestion.

Bile duct

Transports bile to the small intestine.

Small intestine

Site where food is digested and nutrients are absorbed into the blood.

Large intestine

Absorbs water and minerals into the blood.

Mouth

Chews food to begin the digestive process.

Salivary glands

Add enzymes to saliva to aid digestion.

Gullet

Carries food from the mouth to the stomach.

Rectum

Stores faeces before expulsion.

Anus

Expels faeces from the body.

Villi

Increase surface area in the small intestine for nutrient absorption.

Levels of organisation

Cell → tissue → organ → organ system → multicellular organism.

Types of digestive enzymes

Carbohydrase, protease, lipase.

Biological catalyst

Speeds up digestion without being consumed.

Producer

Organism that makes its own food through photosynthesis.

Photosynthesis equation

Carbon dioxide + water → glucose + oxygen.

Commercial use of enzymes

Enzymes in washing powders break down stains.

Greasy stains

Removed by lipase enzymes.

Protein stains

Removed by protease enzymes.

Advantages of enzymes in washing powder

Work at low temperatures, saving energy and money.

Disadvantages of enzymes in washing powder

Potential allergic reactions and damage to natural fabrics.

Exchange surfaces

Areas where materials are exchanged with the environment.

Key features of exchange surfaces

Thin, large surface area, good blood supply.

Waxy layer in leaves

Protects the leaf and reduces water loss.

Epidermis layer in leaves

Transparent, prevents water loss, and acts as a barrier to infection.

Palisade mesophyll layer

Main site of photosynthesis, packed with chloroplasts.

Spongy mesophyll layer

Facilitates gas exchange in leaves.

Stomata

Openings that allow gases to enter and exit the leaf.

Guard cells

Regulate the opening and closing of stomata.

Circulatory system

Transports oxygen and glucose throughout the body.

Blood vessels

Tubular structures that carry blood.

Lumen

Hollow central cavity in blood vessels.

Arteries

Carry blood away from the heart.

Veins

Return blood to the heart.

Capillaries

Connect arteries to veins.

Arteries

Strong with thick walls to withstand high pressure.

Veins

Weaker with relatively thin walls.

Capillaries

Very thin walls, only one cell thick.

Double circulatory system

Blood passes through the heart twice in each circuit.

Heart chambers

Right atrium, left atrium, left ventricle, right ventricle.

Cardiac muscle

Muscle type that makes up the heart.

Heartbeat

Result of coordinated contraction of cardiac muscle cells.

Transpiration

Loss of water vapor from plants.

Transpiration location

Primarily occurs in the leaves.

Transpiration stream

Continuous flow of water from roots to leaves.

Transpiration steps

Water uptake by roots, movement through stem, replacement in leaves, and vapor loss through stomata.

Pressure in xylem

Loss of water reduces pressure at the top.

Stomata opening

Occurs when light and water are abundant.

Stomata closing

Happens when conditions for photosynthesis are poor to conserve water.

Carbohydrase

Turns carbohydrates into sugars

Protease

Turns proteins into amino acids

Lipease

Turns lipids into fatty acids and glycerol