EOY B3 Flashcards
What is a tissue?
Is a group of cells with similar structure and function working together eg:
Glandular tissue- Release substances like enzymes and hormones
Epithelial- Covers the outside of your body as well as internal organs
What is an organ?
Collections of tissues, all working together to perform a specific function eg:
Stomach includes muscular tissue, glandular tissue and epithelial tissue
What are the two main functions of the pancreas?
Makes hormones to control blood sugar as well as the enzymes that digest food.
What is an organ system?
Are groups of organs that all work together to perform specific functions.
Organ systems work together to make an organism. Eg- digestive system, respiratory system
What does the digestive system do?
Exchanges substances with the environment, the food you take in made up off large insoluble molecules. Your body can’t absorb these, so they need to be broken down to form smaller soluble molecules that can be absorbed and used.
Give examples of glands in the digestive system and what they do
Pancreas and Salivary
Make and release digestive juices containing enzymes to break down your food
Where is food mostly digested?
Stomach and small intestine
How is the small intestine adapted to absorb soluble food molecules into the blood?
Very large surface area as it is covered in villi.
It has a good blood supply and a short diffusion distances to blood vessels, increasing diffusion and active transport from small intestine to the blood.
What happens in the large intestine?
Water is absorbed from undigested food into your blood. The material left forms faeces.
Where does the faeces go?
In the rectum and anus
What is the function of the liver?
Production of bile
What main compounds make up a cell?
Carbohydrates
Lipids
Proteins
Carbs, lipids and proteins are all —
Large molecules that are made up by smaller molecules joined together as part of the cell metabolism
What do carbohydrates do?
They provide up with the fuel that makes all other reactions of life possible
What chemicals are carbs made of?
Carbon
Hydrogen
Oxygen
What are all carbs made from ?
Units of sugar
What are simple sugars?
- Some carbs contain only one sugar unit for example C6H12O6
- Other carbs are made of two sugar units joined together, for example sucrose, the compound we call sugar in everyday life.
What are complex carbs?
Such as starch and cellulose are made of long chains of simple sugar units bonded together
Name some carb rich foods
Bread
Potatoes
Rice
Pasta
What will happen to most of the carbs you eat?
Will be broken down into glucose used in cellular respiration to provide energy for metabolic reactions in your cells
Why is the carbohydrate cellulose important?
It is an important support material in plants
What are lipids?
Fats (solids) and oils (liquids)
What is the most efficient energy store and important source of energy?
Lipids
What are lipids important for when combined with other molecules?
Cell membranes
As hormones
In the nervous system
What are lipids made from ?
Carbon
Hydrogen
Oxygen
All lipids are — in water
Insoluble
What molecules are lipids made from?
Three molecules of fatty acids joined to a molecule of glycerol.
The glycerol is always the same but the fatty acids vary.
Name some lipid rich foods
All oils
Butter
Cheese
Cream
The different combo of fatty acids affects whether the lipid will be a liquid oil or a solid fat
What are proteins used for?
Building up the cells and tissues of your body as well as the basis of all your enzymes.
Where is protein found in body?
Tissues like your hair and nails and muscles.
Enzymes
What element is protein made of?
Carbon
Hydrogen
Oxygen
Nitrogen
What are some protein rich foods?
Meat
Fish
Pulses
Cheese
What is a protein molecule made of?
Long chains of small units called amino acids.
There are around 20 amino acids and they are joined into long chains by special bonds.
Different arrangements of the various amino acids give you different proteins
How do proteins make enzymes?
The long chains of amino acids are folded, coiled and twisted into specific 3D shapes. It is these shapes that enable other molecules to fit into the protein. The bonds that hold the proteins in these 3D shapes are very sensitive to temperature and pH and can be easily broken.
If this happens, the shape of the protein is lost and it is denatured
What functions do proteins carry out?
- Structural components of tissues such as muscles and tendons
- Hormones such as insulin
- Antibodies that destroy pathogens and are part of the immune system
- Enzymes which act as catalysts
What is a catalyst?
Speeds up a chemical reaction, but is not used up in the chemical reaction. You can use them over and over again.
What is the lock and key theory?
Simple model of how enzymes work. The substrate to be catalysed fits into the active air of the enzymes like a lock and key.
Enzymes can — small molecules and — large ones
Join
Break up
What is the metabolism?
Sum of all the reactions in a cell or in the body.
What type of metabolic reactions do different enzymes catalyse? (1)
Building large molecules from smaller ones. Includes building starch, glycogen or cellulose from glucose lipids from fatty acids and proteins from amino acids.
Plant cells also combine carbon dioxide and water to make glucose, and use glucose and nitrate ions to make amino acids.
What type of metabolic reactions do different enzymes catalyse? (2)
Changing one molecule into another, includes changing one simple sugar into another such as glucose to fructose and converting one amino acid into another.
What type of metabolic reactions do different enzymes catalyse? (3)
Breaking down large molecules into smaller ones. This includes breaking down carbs, lipids and proteins into their constituent molecules during digestion, breaking down glucose in cellular respiration and breaking down amino acids to form urea and other molecules that can be used in digestion
How many reactions are happening in your cells?
A hundred or more chemical reaction at one time. Each of the different types of reaction is controlled by a different specific enzyme.
Enzymes deliver the control that makes it possible for your cell chemistry to work without one reaction interfering with another.
How can enzymes be affected?
Biological reactions are affected by the same factors as any other chemical reactions. These include concentration, temperature and surface area. However, in living organisms, an increase in temperature only increases the rate of reaction up to a certain point.
The rate of enzyme controlled reactions increases as the temperature increases
True or False
True however for most organisms this is only true up to temperatures of about 40 degrees after this be protein structure of the enzyme is affected by the high temperature. The long amino acid chains begin to unravel and as a result, the shape of the active site changes. It is denatured.
What happens when an enzyme is denatured?
It can no longer work as a catalyst, so the rate of reaction drops dramatically.
What is the optimum temperature of human enzymes?
37 degrees human body temp
What would happen without enzymes?
None of the reactions in your body would happen fast enough to keep you alive. This is why it is dangerous if your temp goes too high when u are ill.
Once your body temp reaches 41 degrees, your enzymes are denatured which will result in death.
Where does the shape of the active site come from?
Force between the diff parts of the protein molecule, these forces hold the folded chains in place.
A change in pH affects forces between different parts of the protein (enzyme) molecule. It changes the shape of the enzyme and the shape of the active site is lost. It is denatured.
Most of your enzymes work — the cells of your body
Inside, controlling the rate of Chem reactions. Digestive enzymes are different, they work outside your cells.
Where are digestive enzymes made?
By specialised cells in glands such as your salivary glands and pancreas and lining of digestive system.
What are enzymes that break down carbs called?
Carbohydrases
What is the most common carb?
Starch, broken down into sugars in mouth and si. This reaction is catalysed by an enzyme called amylase.
What pH does protease in stomach work in?
Acidic conditions
What pH do proteases made in the pancreas work in?
Alkaline conditions
As different enzymes work best in different pH’s, what does the body do?
Makes a variety of different chemicals that help to keep conditions ideal for your enzymes.
How is pepsin made?
Through glands in the lining of the stomach.
What type of enzyme is pepsin?
Protease to digest protein you eat
What pH does pepsin work in?
Acidic
What relatively concentrated solution does the stomach produce?
Hydrochloric acid
Why is hydrochloric acid used ?
Allows your stomach enzymes to work very efficiently.
It also kills most bacteria you take in with your food.
Why does the stomach produce thick layers of mucus?
To coat the stomach walls and protects them from being digested by the acid and the enzymes.
What pH is the small intestine?
Alkaline
How is food from the stomach neutralised before entering the small intestine?
Your liver makes bile which is an alkaline liquid.
It is stored in gall bladder until needed
As food comes into the small intestine from the stomach, bile is squirted onto it through the bile duct.
The bile neutralises the acid that was added to the food in the stomach.
This provides alkaline conditions necessary for enzymes in the small intestine to work most effectively.
It is important for enzymes to have the largest possible surface area of food to work on. This is not problem for carbs and proteins. However the fats that you eat don’t mix with all the watery liquids of the digestive system. They stay as large globules (like oil in water) that make it hard for enzymes to act.
What is the second function of bile?
Emulsifies fats meaning bile physically breaks up large drops of fat into smaller droplets.
This provides a much bigger surface area of fats for the lipase enzymes to act upon.
What is anabolic and catabolic
Catabolic- enzymes that break down
Anabolic- Build up
Substrate
Is the key 🔑🔐
Temperature=
Higher kinetic energy in molecules =
Move around faster =
More collision
State whether big or small-
Starch
Glucose
Protein
Big
Small
Big
