B2a Animal & Plant Tissues

What is a tissue?

A group of similar cells that work together to perform a specific function

What is an organ?

A group of tissues performing specific functions

What is an organ system?

A group of organs working together to form an organism

Give examples of tissues

muscle tissue, nervous tissue

Give examples of organs

heart, stomach, brain

Give examples of organ systems

digestive system, nervous system

What does the digestive system do?

Breaks down and absorbs food

What are enzymes?

Large molecules (proteins) which act as biological catalysts in living organisms

Why do enzymes usually only speed up one reaction?

the shape of the enzyme's active site only matches the reactants for one reaction

What do digestive enzymes do?

convert food into small soluble molecules that can be absorbed into the bloodstream

How would you test food to see if it contains sugars?

The Benedict's test

A + result will be yellow-orange

How would you test food to see if it contains starch?

The iodine test

A + result will be black-purple

How would you test food to see if it contains protein?

The Biuret Reagent test

A + result will be a shade of purple.

What does the heart do?

pump blood around the body

What are the blood vessels that carry blood away from the heart called?

The aorta and the pulmonary artery

Where does the right ventricle of the heart pump blood to?

to the lungs where gas exchange takes place

Where does the left ventricle of the heart pump blood to?

around the rest of the body

Why does the heart have valves?

to make sure blood flows in the right direction (stop it flowing backwards)

How is our heart rate controlled?

by a group of cells located in the right atrium that act as a pacemaker

How are the lungs adapted for gas exchange?

they have a large surface area and a good blood supply

What are the three types of blood vessel called?

arteries, veins, capillaries

Is blood a cell, tissue, or organ?

Tissue

What does blood contain?

plasma with red blood cells, white blood cells and platelets in it

What do red blood cells do?

carry oxygen

What do white blood cells do?

they help the body fight infection

What are platelets?

They are small fragments of cells (no nucleus) which help blood to clot at wounds

Name six types of plant tissue

epidermal tissues

palisade mesophyll

spongy mesophyll

xylem

phloem

meristem tissue

Where is plant epidermal tissue found?

It covers the whole plant

Where is meristem tissue found?

at the growing tips of shoots and roots

What is transpiration?

the evaporation of water from the surface of plants (usually the leaves)

What is translocation in plants?

the movement of sugar around the plant

How would you test food to see if it contains fats?

The Ethanol test

A + result will be cloudy

What do stomata on leaves do?

control the water loss from the plant

What do root hair cells do? (2)

absorb water by osmosis

absorb mineral ions by active transport

What is xylem tissue?

hollow tubes strengthened by lignin adapted for the transport of water

What does xylem tissue do?

transports water and mineral ions from the roots to the stems and leaves

What is phloem tissue?

tubes of elongated cells with pores in the ends

What does phloem tissue do?

transports dissolved sugars from the leaves to the rest of the plant for immediate use or storage

What are the blood vessels that carry blood to the heart called?

The vena cava and the pulmonary vein