SACE Stage 1 Biology Term 1 Test Revision

What are the characteristics of life?

Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition

How did multiorganisms arise?

Archae swallowed a bacteria --\> bacteria acts as a mitochondria --\> archae became bigger and could perform more functions

What is cell theory?

All living organisms are composed of cells
Cells are the basic units of life
All cells arise from pre-existing cells

What is cell differentiation?

Cell differentiation is when stem cells (unspecialised cells) utilise different parts of the DNA sequence to becomme specialised

What are the advantages of multicellular organisms?

- Energy efficient as they don't waste energy to complete necessary functions for life

- Longer lifespans because they are more energetically efficient

- Sexual reroduction and genetic recombination promotes complexity

- Less vulnerable to short-term changes in the environment because they have more systems to cope to the changes and cell death does not necessarily affect survival of organism

- Can grow larger than unicellular organisms

- Increased size and specialisation of limbs mean multicellular oragnisms are more mobile and efficient at locating resources and avoiding predators/negative stimuli

- Can perform more functions

What are the disadvantages of multicellular organisms?

- More cells mean more energy required for survival

- Cells cannot function independently

What is the hierarchical structure in multicellular organisms?

Specialised cells --\> tissues --\> organs --\> systems --\> organism

What are specialised cells?

Cells adapted for a specific job

What are tissues?

Group of similar functioning cells

What are organs?

2 or more tissues that work together to perform specialised tasks

What are systems?

Group of organs working together to perform a common task

What are organisms?

All levels working together to contribute to a successful function

What are the 4 types of tissue?

- Muscle
- Nerve
- Epithelial
- Connective

What do muscle tissue do?

Contract

What do nerve tissue do?

Sense stimuli and transmit signals

What do connective tissue do?

Support and connect structures

What do epithelial tissue do?

Cover internal and external surfaces

What is diffusion?

The passive movement of a substance along its concentration gradient from a region of high concentration to low concentration to create an equilibrium

What is osmosis?

The movement of solvents through a semi-permeable membrane from a region of low concentration to higher concentration resulting in equilibrium

What are the characteristics of an efficient exchange surface?

- Moist
- Vascular (has a blood supply)
- One cell thick (thin)
- Large surface area to volume ratio

What is the order of of the organs in the digestive system?

- Mouth (with teeth

What do secondary organs do in the digestive system?

Help break down food

What are the secondary organs present in the digestive system?

- Liver
- Gallbladder
- Pancreas

Why do we need to eat food?

- Proteins
- Vitamins
- Minerals
- Carbohydrates
- Lipids

What are enzymes?

Enzymes are proteins that act as a catalyst to accelerate chemical reactions

What is the induced fit model?

The induced fit model is when the enzyme's active site undergoes small changes in order to make or break bonds of its substrate and to acheive optimum fit

What is the process of an enzyme bonding with a substrate (enzyme-substrate complex)?

What is denaturation?

Denaturation involes the modifications of the molecular structure of an enzyme which is caused by the breakdown of the weak bonds responsible for the 3D structure of an enzyme.

What are the factors that can cause an enzyme to denature?

- Temperature
- pH
- Presenece of enzyme inhibitors

What is a competetive inhibitor?

A competetive inhibitor competes for an enzyme's active site with its substrate

What is a non-competetive inhibitor?

A non-competetive inhibitor acts on another part of an enzyme

What is an active site?

The restricted region of an enzyme which binds to the substrate

What is mechanical digestion?

Breaks apart food

What is chemical digestion?

Enzymes breaking bonds of specific substrates for digestion

Mechanical digestion in the mouth:

- Chewing: break apart food
- Tongue: moves food around

Chemical digestion in the mouth:

Salivary glands produce saliva in the mouth to digest carbohydrates

Does any digestion occur in the oesophagus?

No

What is peristalsis?

Wavelike contractions of the mucles in the oesophaus which pushes the bolus down to the stomach

Mechanical digestion in the stomach:

Churning of the stomach breaks apart food

Chemical digestion in the stomach:

Hydrochloric acid activates protease

How come the stomach isn't harmed when HCl is present?

Stomach lining produces mucus to protect cells from HCl

What is the function of the liver in the digestive system?

Produces bile

What is the function of the gallbladder?

Stores bile and transfers it to the duodenum of the small intestine

What is the function of bile?

Aids in the breakdown of lipids

What is the function of the pancreas?

Produces digestive enzymes and transports them to the duodenum of the small intestine

What enzymes are produced by the pancreas?

Pancreatic amylase

What is the function of pancreatic amylase?

Breaks down carbohydrates to glucose

What is the function of protease?

Breaks down protein to amino acids

What is the function of lipase?

Breaks down lipids to fatty acids and glycerol

What are the sections of the small intestine called?

Duodenum

What occurs in the duodenum?

Chyme mixes with bile and digestive enzymes from the pancreas to complete nigestion

What occurs in the jejunum?

Nutrient absorption

What occurs in the ileum?

Abosorption of nutrients that were missed in the jejunum

Where is the villi located?

Ileum

What is the function of the ileum?

Absorbs digested food

What are the parts of the villi?

What is the function of lacteal?

Transportation and absorption of fats and lipids

Where is carbohydrate digested?

Mouth and duodenum

What breaks down carbohydrates?

Pancreatic amylase and amylase

What is the product of carbohydrate digestion?

Glucose

Where in the villi are carbohydrates absorbed?

Blood capillaries

Where is protein digested?

Stomach and duodenum

What breaks down protein?

Protease

What is the product of protein break down?

Amino acids

Where in the villi is protein absorbed?

Blood capillaries

Where are lipids digested?

Duodenum

What breaks down lipids?

Bile and lipase

What are the products of lipid break down?

Glycerol and fatty acids

Where in the villi are lipids absorbed?

Lacteal

What occurs in the large intestine?

- Persistalsis moves indigestible waste to the rectum
- Water reabsorption

What are the parts of the heart

What is the function of the heart?

- Generating blood pressure
- Regulating blood supply

What is the function of veins?

Carry blood from the rest of the body to the heart

What is the function of arteries?

Carry blood away from the heart to the rest of the body

What is the function of blood?

Brings oxygen and nutrients to all parts of the body

What is the function of valves in the heart?

Prevent backward flow of blood

Artery Vs. Vein structure

Artery is thick and has a small space to reduce harsh surge of blood to a steadier flow

Vein is thin and has more space to have less resistance to blood flow

Capillaries

- Gas exchange takes place
- One cell thick

Order of blood vessel size

Veins and arteries --\> venules and arterioles --\> capillaries

Pulmonary

Relating to the heart

What is plasma?

Liquid portion of the blood

What does plasma contain?

- Clotting factors
- Hormones
- Antibodies
- Nutrients
- Waste
- Dissolved gases

What are erythorocytes?

Red blood cells

What is the function of erythrocytes?

Carry haemoglobin and oxygen to cells

Where is leukocytes and erythrocytes produced?

Bone marrow

What leukocytes?

White blood cells

What is the function of leukocytes?

Fight infection

What are thrombocytes?

Platelets

What is the function of thrombocytes?

Clot blood by sticking together fibrin

Diastole

Heart refilling with blood and relaxes

Systole

Heart pumping out blood

Anaemia

Lack of iron

Leukaemia

Too many white blood cells (leukocytes)

Haemophilia

Blood can;t clot

Heart murmur

Valve problems

Heart attack

Build up of plaque in the arteries

Function of the respiratory system?

Move oxygen into body tissues for cellular respiration and remove carbon dioxide and other waste products from the cells

What is cellular respiration?

The process of converting glucose into ATP

What are the 3 specialised respiratory structures in multicellular organisms?

Gills - aquatic animals
Spiracles - terrestrial insects
Lungs - most terrestrial verterbrates

Tidal volume

The normal amount of air that is inhaled and exhaled