Unit 2 Biology Flashcards
What are the 7 nutrients? (7)
1- Protein
2- Carbohydrate
3- Lipids (fat)
4- Fibre
5- Vitamins
6- Minerals
7- Water
What is the use of protein in the body? (1)
- They are used for growth and repair of tissues
What is the use of carbohydrates in the body? (2)
- Provide glucose to be used in respiration
- To release energy which is provided to the body
What is the use of lipids in the body? (2)
- Provide insulation
- And serve as long-term energy reserves for the body.
What is the use of fibers in the body? (1)
Supports movement of food through the bowels
What is the use of water in the body? (1)
Hydrates cells and help regulate body temperatures
What is the use of Calcium (mineral) In the body? (1)
Making teeth and bones
What is the use of Iron (mineral) in the body? (1)
Helps make haemoglobin to carry oxygen around the body
What is the use of vitamin A in the body? (1)
It creates a chemical in the eye for good eye vision
What is the use of vitamin C in the body? (2)
- It forms a protein called collagen
- And the collagen helps grow and repair tissues in the body
What is the use of vitamin D in the body? (1)
Helps the bones absorb calcium
What are some sources of protein? (3)
- Egg
- Chicken
- Beef
What are some sources of carbohydrates? (3)
- Rice
- Bread
- Potato
What are some sources of lipids? (3)
- Avocado
- Oil
- Nuts
What are some sources of fibres? (3)
- Fruits
- Vegetables
- Nuts
What are some sources of water? (2)
- Water
- Fruits
What are some sources of Calcium (mineral)? (3)
- Milk
- Vegetable
- Dairy products
What are some sources of Iron (mineral)? (3)
- Beans
- Red meat
- Nuts
What are some sources of vitamin A? (3)
- Carrot
- Butter
- Liver
What are some sources of vitamin C? (3)
- Fruits
- Vegetables
- Potato
What are some sources of vitamin D? (3)
- The sun (is not a source, but helps the body PRODUCE vitamin D)
- Liver
- Egg YOLK
What elements make up carbohydrates? (3)
- Carbon
- Hydrogen
- Oxygen
What elements make up lipids? (3)
- Carbon
- Hydrogen
- Oxygen
What elements make up proteins? (4)
- Carbon
- Hydrogen
- Oxygen
- NITROGEN
What is a monomer and give an example of one (2)
- A small molecule that can COMBINE with others to form a polymer
- Example: Amino acids
What is a polymer and give an example of one (2)
- It is a large molecule made by REPEATING UNITS of small molecules called monomers
- Examples: Proteins and carbohydrates
What are the 3 types of carbohydrates? (3)
- Starch
- Glycogen
- Cellulose
What is the monomer of carbohydrates (including the 3 types)? (1)
Glucose
What forms are starch found as? (2)
- Amylose
- Amylopectin
What makes up lipids? (what are the monomers of lipids?) (2)
- 3 Fatty acids
- 1 Glycerol
NOTE: THESE ARE THE MONOMERS OF LIPIDS. HOWEVER, LIPIDS ARE NOT CONSIDERED AS POLYMERS THEMSELVES
What is the monomer of protein (a polymer)? (1)
Amino acids
How would you test a sample of food to know if carbohydrate (starch) is present? (5)
- First, you would crush the food sample using a pastel and mortar and put it into a dry and clean test tube
- and add some distilled water into the test tube and gently shake it
- Then put 5 drops of IODINE into the test tube
- Observe the colour change and positive result is that the solution will have a blue-black colour
- Negative result is if the solution remains having a orange-brown colour (colour of reagent)
How would you test a sample of food to know if protein is present? (5)
- First, you would crush the food sample using a pastel and mortar and put it into a dry and clean test tube
- and add some distilled water into the test tube and gently shake it
- Then put 5 drops of BIURET REAGENT into the test tube
- Observe the colour change and positive result is that the solution will have a purple colour
- Negative result is if the solution remains having a blue colour (colour of reagent)
How would you test a sample of food to know if reducing sugars (glucose) is present? (6)
- First, you would crush the food sample using a pastel and mortar and put it into a dry and clean test tube
- and add some distilled water into the test tube and gently shake it
- Then put 5 drops of BENEDICTS SOLUTION into the test tube
- Then prepare a hot waterbath and place the test tube in the waterbath for 5 minutes
- Observe the colour change and positive result is that the solution will have either a Green colour (low concentration), Yellow colour (medium concentration), or have a Red colour (high concentration)
- Negative result is if the solution remains having a blue colour (colour of reagent)
- NOTE: This is the main test you need to know and reducing sugars is just another name for glucose
How would you test a sample of food to know if lipids are present? (6)
- First, you would crush the food sample using a pastel and mortar and put it into a dry and clean test tube
- Add ETHANOL into the test tube and gently shake it
- Prepare a separate test tube containing distilled water
-And place the solution from the other test tube into the test tube containing distilled water - Observe the test tube and look for a cloudy white emulsion to form over the solution and if there is, then lipids are present
- Negative result is if the solution remains clear
- NOTE: This is called the emulsion test
Give 2 safety precautions when preforming ALL food tests and explain them (2)
- Wear safety goggles as the reagent used in the test could be an irritant to the eyes
- Carefully place the test tube into the waterbath to prevent hot water from splashing on you
What is a good temperature for the water to be in the waterbath? (1)
80 degrees celsius
What are enzymes? (1)
They are biological catalysts that speed up chemical reactions in living organisms WITHOUT being USED UP in the process
What is a catalyst? (1)
Something that increases the rate of a reaction but remains UNCHANGED at the end of the reaction
What is activation energy? (1)
Minimum energy required for a chemical reaction to occur
What is the active site on an enzyme? (1)
It is an area on the enzyme where a SPECIFIC substrate will bind
What is a substrate? (1)
A molecule that an enzyme works on
What type of molecule are enzymes made up of? (1)
Enzymes are made up of proteins
Describe and explain the process of a substrate binding and making products with an enzyme (6)
- The enzymes active site is complementary to the substrate
- meaning that specific enzymes will ONLY BIND with a specific substrate
- The substrate binds to the enzymes complementary active site ACCORDING to the LOCK AND KEY theory
- Once it is bound to the active site, it is now called an enzyme-substrate complex
- The enzyme catalyses and converts the substrate into products
- After the reaction, the enzyme catalyses with another substrate
How do enzymes speed up chemical reactions? (2)
- Enzymes lower the activation energy required for chemical reactions.
- This makes it easier for substrates to convert into products, speeding up the reaction
How does temperature affect enzyme activity (also talk about when it exceeds optimum temp)? (4)
- A high temperature gives the enzymes more kinetic energy
- This allows the enzyme to have MORE SUCCESSFUL COLLISIONS with substrates
- Due to more successful collisions, reactions with the enzyme and substrate will happen more frequently therefore an increase in the rate of reaction
- However, there is a limitation because if the temperature exceeds the optimum temperature, then the enzyme will start to denature and the rate of reaction starts to decrease
What does denature mean in terms of enzymes? (1)
It is when the shape of the active site on an enzyme changes therefore no substrate will be able to bind with it
How does the PH affect enzyme activity? (2)
- Enzymes work best at their optimum PH, which is specific to each enzyme
- A PH too high or too low can change the enzymes active site shape, causing it to denature.
What is meant by the term deficiency? (1)
Having a lack of essential nutrients needed for health
What deficiency is caused by having a lack of carbohydrates in the body? (1)
Starvation
What does starvation do to the body? (2)
- It causes the body to break down fat and muscle for energy
- leading to muscle loss which weakens the body