1. Unit 2 - organisation

2. Unit 2 Organisational hierarchy – Tissues, organs and organ systems - information
A cell is the basic building block of all multicellular living organisms. Multicellular means made of many cells.
Cells are grouped into tissues…..
A tissue is a group of cells with similar structure and function. Groups of tissues make up organs.
Examples of tissues found in animals include:
■ muscular tissue, which can contract to bring about movement.
■ glandular tissue, which can produce substances such as enzymes, acid and hormones.
■ epithelial tissue, which covers some parts of the body(e.g. skin)
Organs are made of groups of tissues. One organ may contain several tissues.
The stomach is an organ that contains:
■ muscular tissue, to churn the contents.
■ glandular tissue, to produce digestive juices (acid and enzymes)
■ epithelial tissue, to cover the outside and the inside of the stomach.
Organ systems are groups of organs that perform a particular function. The digestive system is one example of a system in which humans and other mammals break down and absorb food into their bloodstream.
Plant organs
Plant organs include stems, roots and leaves.
Plant Tissues
Examples of plant tissues include:
Epidermal tissues, which cover the plant
Mesophyll, which carries out photosynthesis
Xylem carries water and minerals up the stem from the roots to the leaves.
Phloem carries sugars down from the leaves where they are made to the rest of the plant.
A plant organ….roots
Roots absorb water and minerals into a plant.
They also anchor the plant into the ground.
Roots have lots of root hair cells.
Root hair cells increase the surface area of the roots so there is a large surface for the roots to absorb enough water and minerals.
Root hair cells also have thin walls to allow easy passage of water and minerals into the plant.

3. Unit 2 Organisational hierarchy – Tissues, organs and organ systems
Function
Animal/ Plant
Glandular
Secretes substances e.g. acid
Epithelial
Covers surfaces
Epidermal
Mesophyll
In the leaf
Xylem
Transports water and minerals
Phloem
Transports sugars
What is a cell?
Name an cell in humans.
What is a tissue?
Name an tissue in humans.
What is an organ?
Name an organ in humans.
What is an organ system?
Name an organ system in humans.
What are the main organs of a plant?
What is an organ system?
The digestive system’s function is
Label the stomach, small intestine, large intestine,, oesophagus, and mouth.
cells
Cells are the basic building _______ of all living organisms.
A __________ is a group of cells with a similar structure and function.
_____________ are groups of tissues performing specific functions.
Organs are __________ into organ systems,
which work together to form organisms. Missing words: Organs, organised, tissue, blocks
pancreas
Gall bladder

4. Unit 2 - Human digestive system information
Digestive system help sheet.
Some enzymes work outside the body cells.
These are called extracellular enzymes.
They catalyse the breakdown of large molecules into smaller soluble molecules.
Digestion is the process where food is broken down into small soluble products that the body can absorb through the small intestine wall into the bloodstream.
The products of digestion are used to build new carbohydrates, lipids and proteins. Some glucose is used in respiration.
1. Digestion in the mouth
Food is chewed (physical digestion) to create a larger surface area for the action of enzymes.
Saliva is released which contains amylase.
Saliva has a pH of 7.
Amylase digests starch into smaller sugars (glucose).
Further chewing enables swallowing.
The food enters the oesophagus.
3. Digestion and absorption in the small intestine
The small intestine has 2 main jobs:
To complete the digestion of the food
To absorb the soluble products of digestion into the blood.
Digestion in the small intestine
3 juices are released:
1. Bile
Produced by the liver.
Stored in the gall bladder.
Released into the small intestine.
2 main things in bile:
It is Alkali to neutralise the stomach acid and create a pH of 8
Bile salts emulsify fats (convert large fat droplets to small fat droplets) – for a large surface area for the enzymes to act on. Both increase the rate of fat breakdown by lipase. Emulsifying fats is a type of physical digestion.
There are no enzymes in bile.
2. Pancreatic juice and
3. Intestinal juice
Both are released into the small intestine.
Both contain 3 main enzymes:
Amylase to complete the digestion of starch into sugars.
Protease to complete the digestion of proteins into amino acids.
Lipase to break down fats into fatty acids and glycerol.
2. Digestion in the stomach
Food enters the stomach from the
oesophagus.
The walls of our stomach produce juice.
This juice contains:
A protease enzyme (called pepsin).
This digests proteins into amino acids.
Hydrochloric acid – this kills bacteria in our food. It creates pH 2-3.
Mucus – this protects the wall of our stomach from acid and pepsin.
The wall of our stomach is muscular, and churns our food (physical digestion).
The food remains in our stomach for a few hours. The proteins are digested into amino acids.
Food leaves our stomach in small squirts into the small intestine.

5. Unit 2 – Human Digestive system. To help with the table below
CLUES TO HELP
Carbohydrases break down carbohydrates to simple sugars.
Amylase is a carbohydrase which breaks down starch.
Proteases break down proteins to amino acids.
Lipases break down lipids (fats) to glycerol and fatty acids.
Digestive enzymes convert food into _________ soluble molecules that can be absorbed into the ______________. The products of digestion are used to _________ new carbohydrates, lipids and proteins. Some glucose is used in R____________.
Bile is made in the _______ and stored in the __________. It is _________ to neutralise hydrochloric acid from the stomach. It also _________ fat to form _______ droplets which ___________the surface area. The alkaline conditions and large surface area increase the rate of ______ breakdown by _________.
Salivary amylase
8, bile
Chewing
Carbohydrates (starch)
Protein
Glucose
2-3, hydrochloric acid
7, saliva
Amino acids
Emulsifying fats
Churning food
Protease
Fats
Proteins
Carbohydrates
Lipase
Amylase
Fatty acids and glycerol
To help with the table below
Part
Physical digestion
Enzymes made
Food digested
Products of digestion
pH, and substance that creates the pH
Mouth
Stomach
Pancreas X
Gall bladder
Small intestine

6. Unit 2 – Enzymes - information
The effect of pH on enzymes
pH can also affect the shape of the active site.
It does this by affecting the forces that hold the enzyme molecule together.
A change in pH can denature the enzyme.
Different enzymes work best at different pH values (they have different optimum pHs)
Eg. Stomach enzymes work best in acidic conditions.
Mouth enzymes work best in neutral conditions.
Effect of temperature on enzymes
Like most chemical reactions, the rate of enzyme-controlled reactions increases as the temperature increases.
The enzyme and substrates move around faster so they collide more often.
The temperature when the enzyme is working fastest is called the optimum.
This is true up to approximately 40˚C, higher than this and the structure of the enzyme changes.
As a result, the active site becomes a different shape and the substrate no longer fits.
It is then described as denatured.
Enzymes structure and function
Enzymes are biological catalysts.
Catalysts increase the rate of chemical reactions.
Enzymes are protein molecules made up of long chains of amino acids.
These long chains are folded to produce a special shape which enables other molecules to fit into the enzyme.
This shape is vital for the enzymes function.
Normally only one type of molecule (the substrate) will fit into the enzyme.
The active site is the part of the enzyme which the substrate fits into, because it is a certain shape enzymes only fit one substrate (they are specific).
This is how digestive enzymes work
This is how molecules are built up in the body. E.g. muscle tissue

7. Proteins, Catalysts & Enzymes Factors Affecting Enzyme Action.
Unit 2 – Enzymes
Proteins, Catalysts & Enzymes
Factors Affecting Enzyme Action.
Speeding up Digestion
What type of acid is produced in the stomach?
Why is the stomach acidic?
Why wont amylase from the mouth work when it reaches the stomach?
Specificity
Why do enzymes only catalyse a specific reaction?
Mode of action – explain using the lock and key hypothesis how enzymes work.
What are protein molecules made of?
What are enzymes made from?
Enzymes are biological ____________ that __________ up chemical reactions in living organisms
The ___________ in a reaction can be held in the active site and either be connected to another molecule or be broken down.
The warmer the temperature the faster enzymes will work until ______ oC. At temperatures higher than this the enzyme stops working, the enzyme becomes ________________.
Each enzyme works best at a particular _____ value, e.g. enzymes in the mouth have an o_________ pH of ______. Enzymes in the stomach have an o_________ pH of ______.
Explain why an enzyme can’t catalyse a reaction if it is denatured?
What does optimum temperature mean?
What does optimum pH mean?
Write an equation to show how enzymes break molecules down.
Write an equation to show how enzymes build molecules up.
KEY WORDS:
Denatured, Bile, Enzymes, Active site, Substrates , amylase 7

8. Unit 2 – the lungs - information
This is a diagram of the lungs
Label the alveolus
Labels: red blood cell, capillary wall, alveolus wall, alveolus air space, oxygen entering the blood, carbon dioxide leaving the blood, oxygenated blood, deoxygenated blood.
The main wind pipe is called the trachea. It is strengthened by rings of cartilage, these rings prevent the trachea from collapsing. The trachea splits into two branches called bronchi, each one delivers air to each lung. The bronchi split into smaller tubes called bronchioles. Bronchioles end in air sacs called alveoli. Alveoli is the location of gaseous exchange. Gaseous exchange involves the diffusion of oxygen into the blood and carbon dioxide out of the blood. Thee oxygen is delivered to every cell in the body, where it is needed for respiration. The waste gas of respiration is carbon dioxide, this is transported back to the lungs. Carbon dioxide then diffuses into the alveolus and is breathed out.
Deoxygenated blood
Capillary wall
Alveolus wall
Oxygen diffusing into the blood
Direction of blood flow
Alveolus air space
carbon dioxide diffusing out of the blood.
The following points ensure gaseous exchange is efficient
Oxygenated blood
Blood becomes oxygenated in the lungs.
Deoxygenated blood is blood that has no oxygen in it.
Oxygenated blood is blood that has oxygen in it.
Gaseous exchange is by diffusion.
Red blood cell
Alveolus wall
Characteristic
Reason
Large surface area: volume ratio
Increases rate of exchange
Epithelia is 1 cell thic
Short diffusion pathway
Constant movement of air and blood
Maintains diffusion gradient
Moist
Gases dissolve to allow diffusion
How the alveoli are adapted for gaseous exchange…
they have a
large surface area.
moist surface to allow oxygen to dissolve.
thin lining to allow easy diffusion of gases.
Lots of blood capillaries surrounding them for easy gas exchange. 8

9. Unit 2 – the lungs 9 Label the alveolus
Label the diagram of the lungs:
Labels
Trachea
Alveoli
Bronchi
Bronchioles
Label the alveolus
Labels: red blood cell, capillary wall, alveolus wall, alveolus air space, oxygen entering the blood, carbon dioxide leaving the blood, oxygenated blood, deoxygenated blood. 1 3 2 6
Direction of blood flow 8 5
Join up the left side words with their correct meaning or explanation. 9 4
alveolus
bronchi
Bronchioles
trachea
oxygen
carbon dioxide
Ribs
There are thousands of these tiny air-sacs in the lungs
Bronchi divide into two smaller and smaller tubes.
The main breathing tube, it is strengthened by cartilage.
A gas that we need for respiration.
Bones that protect the lungs
Respiration produces this waste gas that moves out of the blood.
The tube between the trachea and a bronchiole 7
Circle the correct word out of each choice. The alveoli have....
A small/large surface area.
A moist/dry surface to allow oxygen to dissolve.
A thin/thick lining to allow easy diffusion of gases.
A few/many blood capillaries surrounding them for easy gas exchange. 9