Bio test study

Question 1

A balanced diet consists of

Answer 1

all of the food groups in the correct proportions

Question 2

The necessary food groups are

Answer 2

Carbohydrates
Proteins
Lipids
Vitamins
Minerals
Dietary Fibre
Water

Question 3

malnutrition is caused by

Answer 3

Not eating a balanced diet

Question 4

types of malnutrition

Answer 4

Starvation
Coronary heart disease
Constipation
Obesity

Question 5

Kwashiorkor

Answer 5

caused by a lack of protein in the diet, most common in children under 2. Often caused by poverty as high protein foods tend to be more expensive and scarcer. Children suffering from kwashiorkor are always underweight for their age but they often have a swollen abdomen as their diet may contain a lot of carbohydrate

Question 6

Marasmus

Answer 6

the most severe form of PEM, where there is a lack of both protein and energy in the diet. People suffering from this have a much lower body weight than normal and look emaciated

Question 7

Dietary need of different individuals

Answer 7

age, activity levels, pregnancy, breast feeding

Question 8

Most of the molecules in living organisms fall into three categories

Answer 8

Carbohydrates, proteins and lipids

Question 9

What do carbs, proteins and lipids all contain

Answer 9

carbon

Question 10

carbohydrates are:

Answer 10

Long chains of simple sugars

Question 11

glucose is a

Answer 11

Simple sugar (monosaccharide)

Question 12

when 2 glucose molecules join together what is formed

Answer 12

Maltose (a disaccharide)

Question 13

when lots of glucose molecules join together

Answer 13

Starch, glycogen or cellulose can form (a polysaccharide)

Question 14

Most fats (lipids) in the body are made up of

Answer 14

triglycerides

Question 15

The basic unit of fat (lipids) are

Answer 15

1 glycerol molecule chemically bonded to 3 fatty acid chains

Question 16

The fatty acids vary in

Answer 16

Size and structure

Question 17

Lipids are divided into

Answer 17

fats (solids at room temperature) and oils (liquids at room temperature)

Question 18

proteins

Answer 18

Long chains of amino acids

Question 19

how many different amino acids are there

Answer 19

About 20

Question 20

when amino acids join together a _____ is formed

Answer 20

Protein

Question 21

test for glucose (reducing sugar)

Answer 21

Add Benedict’s solution into sample solution in test tube
Heat at 60 – 70 °c in water bath for 5 minutes
Take test tube out of water bath and observe the colour
A positive test will show a colour change from blue to orange or brick red

Question 22

Test for starch using iodine

Answer 22

Add drops of iodine solution to the food sample

A positive test will show a colour change from orange-brown to blue-black

Question 23

Test for protien

Answer 23

Add drops of Biuret solution to the food sample

A positive test will show a colour change from blue to violet / purple

Question 24

Test for lipids

Answer 24

Food sample is mixed with 2cm3 of ethanol and shaken
The ethanol is added to an equal volume of cold water
A positive test will show a cloudy emulsion forming

Question 25

test for vitamin C

Answer 25

Add 1cm3 of DCPIP solution to a test tube Add a small amount of food sample (as a solution) A positive test will show the blue colour of the dye disappearing

Question 26

DNA structure

Answer 26

A-T | C-G

Question 27

Water is important for all living organisms because it is a

Answer 27

solvent

Question 28

Enzymes are

Answer 28

. catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction . proteins . biological catalysts

Question 29

Enzymes are necessary because

Answer 29

they speed up reactions such as digestion. Digestion would normally take around 2 weeks but with enzymes it takes 4 hours

Question 30

Enzymes can only work in

Answer 30

the right temperature

Question 31

What is the mechanism that the enzymes use to join called

Answer 31

lock and key mechanism | Only one specific type of enzyme can work with another specific type of substrate

Question 32

food taken into the body goes through

Answer 32

5 different stages during its passage through the alimentary canal (the gut):

Question 33

Ingestion

Answer 33

the taking of substances, e.g. food and drink, into the body through the mouth

Question 34

Mechanical digestion

Answer 34

the breakdown of food into smaller pieces without chemical change to the food molecules

Question 35

Chemical digestinon

Answer 35

the breakdown of large, insoluble molecules into small, soluble molecules

Question 36

Absorbtion

Answer 36

the movement of small food molecules and ions through the wall of the intestine into the blood

Question 37

assimilation

Answer 37

The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

Question 38

egestion

Answer 38

the passing out of food that has not been digested or absorbed, as faeces, through the anus

Question 39

Plants contain ___ types of transport vessel

Answer 39

two

Question 40

Xylem vessels

Answer 40

transport water and minerals (pronounced: zi-lem) from the roots to the stem and leaves

Question 41

Phloem vessels

Answer 41

transport food materials (mainly sucrose and amino acids) made by the plant from photosynthesising leaves to non-photosynthesising regions in the roots and stem (pronounced: flow-em)

Question 42

Root hair cells take up

Answer 42

water via osmosis

Question 43

Transpiration has many functions in plants such as

Answer 43

transporting mineral ions providing water to keep cells turgid in order to support the structure of the plant providing water to leaf cells for photosynthesis keeping the leaves cool (the conversion of water (liquid) into water vapour (gas) as it leaves the cells and enters the airspace requires heat energy. The using up of heat to convert water into water vapour helps to cool the plant down)

Question 44

how does transpiration occur

Answer 44

Evaporation takes place from the surfaces of spongy mesophyll cells The many interconnecting air spaces between these cells and the stomata creates a large surface area This means evaporation can happen rapidly when stomata are open

Question 45

How is the transpiration steam created

Answer 45

Water molecules are attracted to each other by cohesion – creating a continuous column of water up the plant Water moves through the xylem vessels in a continuous transpiration stream from roots to leaves via the stem Transpiration produces a tension or ‘pull’ on the water in the xylem vessels by the leaves As water molecules are held together by cohesive forces (each individual molecule ‘pulls’ on the one below it), so water is pulled up through the plant If the rate of transpiration from the leaves increases, water molecules are pulled up the xylem vessels quicker

Question 46

wilting

Answer 46

If more water evaporates from the leaves of a plant than is available in the soil to move into the root by osmosis, then wilting will occur This is when all the cells of the plant are not full of water, so the strength of the cell walls cannot support the plant and it starts to collapse