S1 Food Science TEST Flashcards
SIMPLE CARBOHYDRATES
Breaks down QUICKLY into the GLUCOSE needed for respiration.
COMPLEX CARBOHYDRATES
Breaks down SLOWLY into the GLUCOSE needed for respiration.
PROTEINS
Breaks down into AMINO ACIDS which form new proteins used in many life processes.
Eg. Meat
VITAMINS & MINERALS
Needed in very small amounts to keep you healthy.
WATER
Used to make bodily fluids, allows chemicals to react in cells, and gives them shape.
Eg. Drinks
Balanced diet
A balanced diet means eating a good range of the different nutrients/ food groups.
LIPIDS (FATS)
Stored in fat cells. If there
is no CARBOHYDRATE, fat breaks down into the GLUCOSE needed for respiration.
FIBRE
NOT digested, but keeps food moving. Gut bacteria feed off it.
Eg. Anything plant-based
Energy in food
Food is a chemical store. Organisms need energy to reproduce, grow and move.
units of energy
Kilojoules (kJ) and Kilocalories (kcal)
Kilocalories
Kilocalories is often just called calories in everyday life.
= 1 kcal
4.2 kJ = 1 kcal
k is the abbreviation for
k is the abbreviation for kilo which means a thousand.
1 kJ
1 kJ = 1000 J
Measuring Energy in food
The amount of thermal energy released from combusting (burning) food can be used to measure the amount of energy in its chemical store.
How do you measure energy in food?
We can do this by heating water in a boiling tube using burning food and then measuring the increase in temperature of the water.
How do you measure energy in food? (Diagram)
Independent Variable
The variable you decide to change.
Dependent Variable
The variable that changes because you changed the independent variable.
Control variable
A variable that needs to be kept the same. Changing it will affect the results.
Independent variable Burning Crisps
Type of crisp.
Burning Crisps Dependent variable
Temperature change of the water.
Burning Crisps Control Variable 1
Mass of crisp.
Burning Crisps Control Variable 2
Complete combustion of crisp
Burning Crisps Control Variable 3
Distance of crisp from water.
Why do living things need energy?
Living things need energy in order to carry out the 7 life processes; movement, respiration, sensitivity, growth, reproduction, excretion and nutrition.
How much energy is required can depend on
How much energy is required can depend on many different factors.
BMR
Basal Metabolic Rate
Basal Metabolic Rate
Basal Metabolic Rate is the rate at which energy is used up when the body is at rest.
BMR is an estimate of how many calories you’d burn if you were to do nothing but rest for 24 hours.
It represents the minimum amount of energy needed to keep your body functioning, including breathing and keeping your heart beating.
unbalanced diet
An unbalanced diet is one that does not contain the right amount of nutrients for an individual.
malnutrition
caused by unbalanced diet It can lead to malnutrition. You can either be:
not getting enough nutrients (lack)
getting more nutrients than needed (excess)
Whether or not a diet is balanced depends on several factors, such as:
Age
Lifestyle
Size
Metabolism
Some hormones
Some medicines
Some diseases
MOUTH
Chews food and adds saliva.
Start of carbohydrate break down.
LIVER
Produces bile, that is released in the entrance of the small intestine to help break down lipids
SMALL INTESTINE
Carbohydrates, proteins and lipids molecules are broken down and absorbed into the bloodstream.
STOMACH
Adds acid to kill bacteria and allows digestive chemicals to work. Churns to mix. Start of protein digestion.
PANCREAS
Produces digestive chemicals which aid the digestion of carbohydrates, proteins and lipids.
LARGE INTESTINE
Water is absorbed back into the bloodstream from what is left of the food.
Acids
Acids are substances that taste sour.
Household acids include lemon juice, apples, vinegar and fizzy drinks.
Alkalis
Alkalis are the opposite of an acid.
An alkali is a substance that can feel soapy to touch.
Common household alkalis include oven cleaner, bleach and toothpaste.
Indicators
Indicators are solutions that change colour whether an acid or alkali is present.
Indicator Methyl orange
Colour in acid Red
Colour in alkali Yellow
IndicatorPhenolphthalein
Colour in acidColourless
Colour in alkaliPink
IndicatorUniversal indicator
Colour in acidRed
Colour in alkaliBlue
What is the pH scale?
pH scale measures how acidic or alkaline a solution is. Solutions have a pH between 1 and 14.
What is an Acid?
Acids are a group of compounds with a pH less than 7. Acids are solutions which contain hydrogen ions (H+). Acids have a sour taste.
Examples include: orange juice and vinegar.
What is an Alkali?
Alkalis are a group of compounds with a pH greater than 7. Alkalis contain hydroxide ions (OH-). Alkalis feel soapy to touch.
Examples include: bleach and toothpaste
How hazardous is a substance?
If an acid has a small pH, the more hazardous.
If an alkali has a large pH, the more hazardous.
The closer a pH value is to 7, the less hazardous a substance is.
Describing Substances
We can described a substance with a pH lower than 7 as an acid or as being acidic.
We can described a substance with a pH greater than 7 as an alkali or as being alkaline.
To neutralise an acid:
Add a small volume of an alkali to the acid
Stir the solution and use the stirring rod to test the pH on pH paper
Continue to repeat steps 1 & 2 until the substance is nearly neutral. At this point, add the alkali a couple of drops at a time, until the solution is pH 7.
neutralisation
If an acid is added to an alkali (in the right quantity) it will neutralise the substance, making water.
This is how antacids treat indigestion (too much acid in the stomach)
