6.3.5 Chemical digestion

Chemical digestion

Core

• State the significance of chemical digestion in 

the alimentary canal in producing small, soluble 

molecules that can be absorbed

• State where, in the alimentary canal, amylase, 

protease and lipase enzymes are secreted

• State the functions of a typical amylase, a 

protease and a lipase, listing the substrate and 

end-products

Chemical digestion in the alimentary canal turns large insoluble molecules into smaller water soluble molecules by breaking them down with enzymes in the mouth, stomach and small intestine.

Amylase is secreted in the mouth and small intestine

Protease is secreted in the stomach and small intestine

Lipase is secreted in the small intestine

Protease may turn a protein into amino acids

Lipase may turn a fat into fatty acids and glycerol

Amylase may turn Starch into maltose

6.3.4 Mechanical and physical digestion (Unfinished)

Mechanical and physical digestion

Core

• Define digestion

• Describe the role of longitudinal and circular 

muscles in peristalsis

• Outline the role of bile in emulsifying fats, 

to increase the surface area for the action of 

enzymes

Digestion is the breaking down of food molecules into smaller food molecules in the Alimentary Canal. These molecules are broken down from large insoluble molecules into smaller water - soluble molecules using chemical and mechanical processes.

6.3.3 Human Alimentary Canal

Human Alimentary Canal

Core

Define Ingestion

Define egestion

Identify the main regions of the alimentary canal 

and associated organs

Identify the main regions of the alimentary canal 

and associated organs

Ingestion is the taking in of food to the body through the mouth.

Egestion is the passing of food out of the body which has not been digested, it leaves in the feaces through the anus.

Food enters the mouth and is turned into a bolus with the help of Saliva which contains mucus, Amalayse and water. The amalayse breaks down starch in the food into mucusand the mucus lubricates the food so that it can easily pass through the esophagus. Once food is ready to be swallowed, a sphincter muscle covering the esophagus opens and food travels into the Stomach. In the Stomach the food is made into Chyme with the help of protease. The proteins in the food are broken down into smaller and smaller molecules with the help of hydroclhoric acid (which helps the protease to fuction in the correct PH) Once the food has been broken down into chyme it is passed into the Small intestine where Pancreatic juice and bile are secreted. In the Pancreatic juice is an alkaline substance which neutralizes the churn so that amalayse and lipase may work on it. Bile emulsifies the churn, breaking down fats into smaller molecules for the lipase to have an easier job of working on it.

6.3.1 Diet (unfinished)

Diet

Core

• State what is meant by the term balanced diet 

and describe a balanced diet related to age, sex 

and activity of an individual

• Describe the effects of malnutrition in relation to 

starvation, coronary heart disease, constipation 

and obesity

A balanced diet is a diet in which A person is receiving all the nutrients required for proper growth. Different people may have different requirements in terms of their diet, for example a Pregnant women may need to eat more than a man (the average woman requires less than a man, unless pregnant or ill) If a person has a job which requires a lot of movement, then they will obviously need to eat a diet consisting of more carbohydrates, however a person who is sat down for the majority of the day will need to eat less as he will be burning less.

6.2.3 Mineral Requirements

Mineral Requirements

Core

• Describe the importance of:

• nitrate ions for protein synthesis

• magnesium ions for chlorophyll synthesis

Extended

• Explain the effects of nitrate ion and 

magnesium ion deficiency on plant growth

Nitrate ions and Magnesium ions are taken from the soil by either diffusion or active transport. Nitrate ions are primarily used for making proteins whereas magnesium ions are primarily used to produce chlorophyll.

A lack of Nitrate ions will result in not enough proteins being produced, and will result in weak growth/yellow leaves. A lack of Magnesium ions will result in not enough chlorophyll being produced, limiting the rate of photosynthesis and resulting in yellowing between the veins in the leaves of plants.

6.2.2 Leaf Structure

Leaf Structure

• Identify and label the cuticle, cellular and tissue 

structure of a dicotyledonous leaf, as seen in 

cross-section under the light microscope, and 

describe the significance of these features in 

terms of functions, to include:

• distribution of chloroplasts – photosynthesis

• stomata and mesophyll cells – gas exchange

• vascular bundles (xylem and phloem) – transport 

and support

The cuticle prevents water loss via evaporation as it has a waxy layer which prevents water from getting too hot.

Chloroplasts (chlorophyll inside them) trap sunlight and carry out the process known as photosynthesis - more chloroplasts and enough raw materials and light to support them will mean a higher rate of photosynthesis 

Stomata open to allow gases to diffuse inside the plant leaf, the mesophyll cells all contain chloroplast and so C02 which has diffused into the leaf through the Stomata will eventually reach the Mesophyll cells and contribute to photosynthesis.

Xylem are involved in water uptake. There is always a lower pressure level at the top of the Xylem as a result of transpiration, this means that water is constantly moving up the Xylem tubing towards the leaves from the soil/root hair cells.

Phloem transport sucrose around the plant from places of production to sinks.

6.2 Photosynthesis

Photosynthesis

Core

Define Photosynthesis

State the word equation for the production of 

simple sugars and oxygen

Describe the intake of carbon dioxide and water 

by plants

Explain that chlorophyll traps light energy 

and converts it into chemical energy for the 

formation of carbohydrates and their subsequent 

storage

Extended

State the balanced equation for 

photosynthesis in symbols

Investigate and state the effect of varying 

light intensity, carbon dioxide concentration 

and temperature on the rate of photosynthesis 

(e.g. in submerged aquatic plants)

Define the term limiting factor as something 

present in the environment in such short 

supply that it restricts life processes

Explain the concept of limiting factors in 

photosynthesis

--------------------------------------------------------------------------------

Photosynthesis is the process by which plants produce Carbohydrates from raw materials by trapping light.

Word Equation for simple sugars and oxygen

Carbon Dioxide + Water --------> Glucose + Oxygen

Water is taken from soil by root hair cells, this water travels up the xylem tubing since there is a lower pressure at the top (transpiration causing water on leaves of plant to evaporate meaning there is a lower pressure up, constantly) Carbon Dioxide is taken into the plant by process of diffusion whilst Stomata on the plant leaves are open, the C02 diffuses into the plant leaves and spreads around.

Varying light intensity on a plant may adversely damage it. If an plant only receives a very low level of light, it will not photosynthesize as much as a plant in normal light and this is because there is less light being converted into chemical energy for the plant to actually undergo the process of photosynthesis. Low levels of C02 would also adversely affect the plant as it would be missing one half of the requirements for photosynthesis. Although too much of these two substances would not harm the plant, at a certain point the rate of photosynthesis neither speeds up or decreases. Low temperature means chemical reactions can not take place as fast as normal and so the rate of photosynthesis is decreased, once again though a certain point is reached as temperature increases and the rate of photosynthesis will no longer increase.

A limiting factor is a factor of the environment which has a certain impact on the rate of photosynthesis of a plant. For example C02 and Temperature can be limiting factors if they are low (temp) or sparsely found (levels of C02) 

6. Nutrition

Nutrition

Core

Define Nutrition

Nutrition is the ability of an organism to take in nutrient molecules containing raw materials or energy for growth/tissue repair and then absorbing/assimilating them. An example could be a plants ability to take in Magnesium Ions from soil and use them to produce Chlorophyll.

5. Enzymes

Enzymes

Core

Define the term catalyst

Define the term Enzyme

Investigate and describe the effect of changes in 

temperature and pH on enzyme activity

Extended

Explain enzyme action in terms of the ‘lock 

and key’ model

Explain the effect of changes in temperature 

and pH on enzyme activity.

Describe the role of enzymes in the 

germination of seeds, and their uses in 

biological washing products and in the food 

industry (including pectinase and fruit juice)

Outline the use of microorganisms and 

fermenters to manufacture the antibiotic 

penicillin and enzymes for use in biological 

washing powders

Describe the role of the fungus Penicillium in 

the production of antibiotic penicillin

A catalyst is a substance which speeds up a chemical reaction, an enzyme is an example of one of these. Catalysts are also not changed by reactions.

An enzyme is a protein and biological catalyst which speeds up chemical reactions in the body, without them, reactions would take place far to slow for life to take place.

Enzymes have an optimum PH and Temperature to work in, any change to this could result in Enzymes being denatured which means that it has basically changed shape so much, that it's substrate can no longer fit into it. The optimum Temperature for enzymes is 37 degrees Celsius which also just happens to be our internal body temperature.

Extended

The lock and key method is fairly easy to understand (consult picture above right) In essence, an enzyme is like a lock and a certain substrate is that enzyme's matching key. The substrate (molecule being worked on) 

attaches itself to the enzyme's 

active site. This is now known as an enzyme - substrate complex, after a while the enzyme will change shape slightly and release products.

As temperature increases past an enzymes optimum working temperature the rate of reaction will slow down and eventually (if temperature keeps increasing) the enzyme will denature and will no longer fit any substrate.

4.3 Osmosis (Unfinished)

Osmosis

  Core

• Define osmosis

• Describe the importance of osmosis in the 

 uptake of water by plants, and its effects on 

 plant and animal tissues

  Extended

• Describe and explain the importance of a 

  water potential gradient in the uptake of water 

  by plants

Osmosis can be define as the net movement of water molecules from an area of low water concentration to that of a higher one.

Osmosis is clearly very important to plant as, without it obtaining water would be either very difficult or impossible. Osmosis provides a medium for which water can be simply retrieved from nearby soil by root hair cells.

A water potential gradient ensures that no water is lost from root hair cells when it is being absorbed. It also makes sure that water does not simply leak out of cells, 

4.2 Active Transport (Unfinished?)

Active Transport

Extended

• Define active transport
• Discuss the importance of active transport
as an energy-consuming process by which
substances are transported against a
concentration gradient, e.g. ion uptake by root
hairs and uptake of glucose by epithelial cells
of villi

Active Transport is when a substance is taken from an area of lower concentration to that of higher concentration against its concentration gradient, as its name suggests this process requires energy released from respiration.

Without the possibility of Active Transport plants would not be able to take in certain minerals found in small amounts in soil near them, this would cause them to wilt and eventually die.

4.1 Diffusion

4.1 Diffusion

Core

• Define Diffusion

• Describe the importance of diffusion of gases 

and solutes and of water as a solvent

Diffusion can be defined as the net movement of particles from an area of high concentration to one of low concentration down a concentration gradient. An example could be the diffusion of gasses from the air into leaves through Stomata. In the air there is a higher amount of Carbon Dioxide than there is in leaves. Therefore the C02 moves down its concentration gradient (High-Low) from the air, through the stomata and into the leaf. We say that the C02 has diffused into the leaf.

Diffusion is incredibly important to life. When we respire we produce Carbon Dioxide and this must be excreted as it is bad for cells and would damage them, C02 rich blood is taken to the lungs and diffused out of the blood by alveoli, it is then excreted by the lungs. Without diffusion, manylife processes could not take place.

Size of Specimens

Size of Specimens

Levels of Organisation

Levels of Organisation

Core
• Relate the structure of the following to their
functions:
• ciliated cells – in respiratory tract
• root hair cells – absorption
• xylem vessels – conduction and support
• muscle cells – contraction
• red blood cells – transport

Define:
• tissue
• organ
• organ system

Ciliated Cells - These are cells with tiny cilia. Many cilia can be found in your throat and are generally used for pushing substances along e.g mucus when you have a cold. They can also be found on the lining of the intestines but that is more for the absorption of enzymes (discussed later)

Root Hair Cells - These Cells absorb water and nutrients from surrounding soil to benefit the plant. It absorbs water by process of Osmosis, down a water concentration gradient.

Xylem Vessels - Once water has been absorbed into the plant root hair cell, it proceeds to the Xylem. At the top of the Xylem is a low pressure whereas at the bottom is a higher pressure, this causes water to flow up the Xylem to the rest of the plant.

Muscle Cells - These are the cells which make up muscles. They are generally used for movement/contraction. Cells make up a tissue and the main feature of muscle tissues is their ability to shorten/contract to promote movement.

Red Blood Cells - The main function of Red blood cells is to transport Haemoglobin. Once Oxygen has gone through the Lungs, it is Oxygenated and contains Haemoglobin, it takes this Haemoglobin to other cells around the body and oxygenates them. Red blood cells contain no nucleus and have a biconcave shape, both of these features allow for a larger surface area in which to carry Haemoglobin. Red blood cells are also very small, which means they can fit through even the tiniest of Capillaries and oxygenate every cell in the body.

Tissue -  a group of cells with similar structures, working together to perform a shared function.

Organ - This can be defined a as a group of tissues working together to perform a single bodily function. The lungs oxygenating blood could be seen as one example.

Organ System - This can be defined as a group of organs working in a system to carry out body functions. The organs involved must have similar functions and work towards the same goal for example, all the organs in the Circulatory System.

Section II: Organisation and maintenance of the organism

  

Cell structure and organisation

Core

1.Know what Living Organisms are made from

2.Identify and Describe the structure of a Palisade cell and a Liver Cell

3.Describe the differences in structure between an animal cell and plant cell

Extended

1.Relate the structures seen under the light 

microscope in the plant cell and in the animal 

cell to their functions

All living organisms are made from cells although they do vary, we will be looking at the differences between a plant cell and animal cell in detail. There aren't too many parts to remember in a simple plant cell so lets get to it. 

Nucleus - This is where the genetic information of the organism is stored. This aids the cell in creating the correct types of proteins. The genetic information from a nucleus is kept in Chromosomes which are made of DNA inherited from the organisms parents.

Vacuole - The vacuole contains cell sap and within cell sap are a collection of sugars and other such substances in solution. The vacuole also pushes on the cell, keeping it in shape.

Mitochondria - These can be known as the 'powerhouse' of the cell. Inside Mitochondria Oxygen is used to release energy from Glucose in a process known as aerobic respiration. Unsurprisingly, cells which need a lot of energy/use a lot of energy (Sperm Cells for example) require a lot of Mitochondria.

Chloroplast - Within Chloroplast is the pigment Chlorophyll which is in fact what makes plant leaves green. Chloroplast are the location of Photosynthesis in a plant, this is where sunlight is trapped and combined with Water and Carbon Dioxide to produce Glucose. Glucose is then converted to Starch or Sucrose for reasons which will be discussed later (Mainly they are simply better at storage/transport) 

Cytoplasm - Cytoplasm is the area where many different metabolic reactions take place (photosynthesis, respiration) and it contains many substances dissolved in it, mainly proteins.

Cell Membrane - The cell membranes job is to control what enters/leaves the cell - you may have thought that would be the job of the cell wall, not so as the cell wall is what we call 'fully permeable' this means it allows any and all substances through it whereas the membrane is 'partially permeable' only allowing substances of a certain size through.

Cell Wall - The job of the cell wall is the protect the cell as a whole, the cell wall is made of cellulose which fibers which criss-cross over one another to form a very strong protective layer. For example if the cell takes in too much water by Osmosis, the cell wall will stop the cell wall from bursting when it swells.

Ribosomes - These are the places where Proteins are made. Upon receiving instructions from the nucleus detailing what proteins need to be produced, Ribosomes join many amino acids together in a long chain.

Starch Grains (Not on Diagram) - Chloroplast often contain grains of Starch which have been made by photosynthesis, they are basically molecules glucose which have been converted to Starch for Storage (food storage for the cell).

Glycogen (Not on Diagram) - Animal cells contain these as opposed to starch and are once again molecules of glucose which have been converted for storage.

What's The Difference?

It's pretty Simple,below is a list of things you will find in an Animal Cell and things you will find a plant cell.

Ribosomes - A & P

Cytoplasm - A & P

Membrane - A & P

Wall - P

Nucleus - A & P

Mitochondria - A & P

Chloroplast - A

Vacuole - P (smaller versions can be found in animal cells as well)

Starch Grains - P

Glycogen -  A

2.1/.2 Classification and Diversity of Living Organisms

2 Classification and Diversity of Living Organisms:

2.1 Concept and use of a classificatory system:

1.Define the Binomial Naming System

2.List main features of Vertebrates and Invertebrates 

Extended:

1.List the main features used in the classification of the following groups: 

viruses, bacteria and fungi, and their adaptation to the environment, as 

appropriate

2.Know that there are other classification 

systems

Section 1 (In Entirety)

Section 1:

Core
 List and describe the characteristics of living organisms
 Define the terms:
• Nutrition
• Excretion
• Respiration
• Sensitivity
• Growth
• Movement

Nutrition is the taking in of nutrients (Proteins, minerals etc.) and digesting/assimilating of them for use in cells.

Excretion could be defined as the removal of waste products (that have undergone digestion) from the body. Something which has not been digested and is removed from the body is Egested.

Respiration could be defined as the chemical breakdown of nutrient molecules to create energy for muscles and other such life processes to work/happen in the body.

Sensitivity would generally be defined as an organisms responses to stimulus from changes in the external or internal environment.

Growth is a permanent increase in the size of an organism by an increase in cell number, cell size or both.

Movement is the ability of an organism to change it's positioning or place.

These may seem daunting at first to remember so an easy pneumonic to aid your memory is MRS. GREN.

Questions may ask you whether or not an organism is considered to be living if it does not for example respire, or grow and the short answer is no - however the situation can get more complex when we look at viruses later in the Section.