Biology-paper 1 CELL ORGANISATION

What are large multicellular organisms made of?

Organ systems.

What are cells?

How are organ systems created?

Basic building blocks that make up all living organisms.

Specialised cells form tissues, which forms organs, which form organ systems and organ systems can make entire organisms (e,g human.)

In large multicellular organisms what do the different systems inside them do?

What’s a tissue?

Exchanging and transporting materials.

A group of similar cells that work together to carry out a particular function, it includes more than one type of cell.

In mammals which three tissues include?

Muscular tissue- which contracts to move whatever it is attached to.

Glandular tissue- which makes and secretes chemicals like enzymes and hormones.

Epithelial tissue- covers some parts of the body. (e.g inside the gut.)

What’s an organ?

An organ is a group of different tissues that work together to perform a certain function.

The stomach is an example of an organ what is it made of?

Muscular tissue- which moves the stomach well to churn up the food.

Glandular tissue- which makes digestive juices to digest food.

Epithelial tissue- which covers the outside and inside of the stomach.

What’s an organ system?

A group of organs working together to perform a particular function.

The digestive system is an example of an organ system, what does it do and what is it made of?

It breaks down and absorbs food. It’s made up of:

Glands- (e.g the pancreas and salivary glands) which produce digestive juices.

The stomach and small intestine- which digest food.

The liver- which produces bile.

The small intestine- absorbs soluble food molecules.

Large intestine- absorbs water from undigested food, leaving faeces.

Organ systems work together to create what?

Whole organisms such as a human.

What is an enzyme?

What is a catalyst?

Enzymes of biological catalysts produced by Living things.

A catalyst is a substance which increases the speed of a reaction without being changed or used up in the reaction.

Why do living things produce enzymes that act as biological catalysts?

Because enzymes reduce the need for high temperatures and the enzymes only speed up the useful chemical reactions in the body, not the unwanted ones too it also doesn’t damage the other cells.

Enzymes are all large proteins. Meaning they are made up of what?

Chains of amino acids. These chains are folded into unique shapes which enzymes need to do their jobs. It’s called the lock and key model.

How does an enzyme work when it catalyses a reaction?

Enzymes usually only catalyse one specific reaction because the substrate has to fit into the enzymes active site. If the substrate and active site don’t match the reaction won’t be catalysed.

What is the active site?

What is a substrate?

The active site has a unique Shape (on the enzyme) that fit fits onto the substance involved in a reaction.

A substrate is the substance that an enzyme acts on in reactions. It’s usually split apart or joined together.

What happens to the enzyme after the reaction?

It is unchanged.

What’s two factors affect the rate of enzyme catalysed reactions?

Temperature and pH.

How does temperature affect the rate of an enzyme catalysed reaction?

A higher temperature increases the rate of reaction at first. If it gets too hot, some of the buns holding the enzyme together break-Which changes the shape of the enzymes active site so the substrate won’t fit anymore meaning it has denatured. All enzymes have an optimum temperature they work best at.

How does pH affect the rate of enzyme catalysed reactions?

If Ph is too high or too low it damages the bonds in the enzyme which then Changes the shape of the active site and denatures the enzyme.

All enzymes have an optimum Ph they work best at. It’s often neutral pH seven but not always. E.g Pepsi works in the stomach where th There are acidic conditions and works best at Ph 2.

What do digestive enzymes breakdown into?

Give three examples of big molecules.

Big molecules.

Starch, proteins and fats.

Big molecules are too big to pass through the walls of the digestive system so what happens?

The digestive enzymes break these big molecules down into smaller ones like sugars, amino acids, glycerol, and fatty acids. These smaller soluble molecules can pass easily through the walls of the digestive system, allowing them to be absorbed into the bloodstream.

Different enzymes catalyse the breakdown of different food molecules. What does amylase breakdown?

Amylase an example of a Carbohydrase. Breaks down starch into maltose (and other sugars).

What does protease break down?

What does lipase break down?

It breaks down protein into amino acids.

It breaks down Lipids into glycerol and fatty acids.

What can a products of digestion (carbohydrates, lipids, proteins) be used for?

They can be used to make new carbohydrates, proteins and lipids some of the glucose (a carbohydrate) that’s made is used in respiration.

Bile which is produced in the liver does what?

Why does the small intestine need bile?

Neutralises the stomach acid and emulsifies fat. It is stored in the gall bladder before it’s released into the small intestine.

🩷 The hydrochloric acid in the stomach makes the pH to acidic for enzymes in the small intestine to work Properly. Bile is alkaline meaning it neutralises the acid and makes conditions alkaline the enzymes in this morning testing work best in these alkaline conditions.

🩷 Bile also emulsifies fats (breaks it down into small tiny droplets). This gives a much bigger SA of fat for the enzyme Lipa to work on which makes its digestion faster.

Where are enzymes used in the digestive system produced?

Why specialised cells and glands and in the gut lining. These are released into the gut where they mix and help to breakdown food.

What do the saliva glands do?

What does the gullet do?

What does the liver do?

These produce analyse enzyme in the saliva.

The gullet also known as the oesophagus connects the stomach and mouth.

Deliveries where bile is produced by neutralise the stomach acid and emulsifies fat.

What does the gallbladder do?

What does the Large intestine do?

What does the rectum do?

It is where bile is stored before it is released into the small intestine.

The large intestine is where excess water is absorbed from the food.

Rectum is where faeces are stored before they go through the anus.

What does the stomach do?

1. It pummels the food with its muscular walls.

2. It produces the protein enzyme Pepsin.

3. It produces hydrochloric acid to kill bacteria and give the right pH for the protease enzyme to work (pH 2- acidic)

What does the pancreas do?

Produces proteins and malaise and lipase enzymes. It releases these into the small intestine.

What does the small intestine do?

1. It produces proteins, analyse and lipase enzymes to complete the digestion.

2. This is also where the digested food is absorbed out of the digestive system into the blood.

What is the thorax?

Where are the lungs?

The thorax is the top part of your body. It is separated from the lower part of the body by the diaphragm.

The lungs are found in the thorax protected by the rib cage.

Where does the air that you breathe go?

It goes through the trachea, The splits into two tubes called bronchi ( the collective name for each one which are called a bronchus) One going to each lung, the bronchi splits into progressively smaller tubes called the bronchioles the bronchioles and a smaller air sacs called alveoli.

What do the lungs have?

Millions of alveoli surrounded by a network of blood capillaries.

The blood Which passes next to the alveoli returns to the lungs from where?

What does this mean?

It returns to the lungs from the rest of the body so it contains lots of carbon dioxide and very little oxygen.

1. So oxygen diffuses out of the alveolus (High concentration) Into the blood (Low concentration) to be breathed out.

2. When the blood reaches body cells, oxygen is released from the red blood cells (High concentration) and diffuses into the body cells (Low concentration).

3. At the same time, carbon dioxide diffuses out of the Body cells (High concentration) into the blood (Low concentration). It’s then carried back to the lungs.