Biochemistry 1st year Topic 3 Flashcards

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1
Q

What is an organic molecule?

A

A molecule containing carbon and hydrogen

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2
Q

What is an inorganic molecule?

A

A molecule without carbon and hydrogen

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3
Q

What are the 3 most common elements that make up biological structures?

A

Carbon
Hydrogen
Oxygen

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4
Q

However the body needs other elements to build up proteins and other structures. Mention a few.

A

Calcium,potassium,phosphorus,nitrogen,sulfur,iron etc

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5
Q

What are the 3 most common nutrients?

A

Carbohydrates,proteins and lipids

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6
Q

What are carbohydates made up of and how can we divide them?

A

carbon
hydrogen
oxygen

monosaccharides
disaccharides
polysaccharides

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7
Q

Describe the structure of monosaccharides, disaccharides and polysaccharides.

A

Monosaccharides: only contain 1 carbon ring in their atoms. (simple sugar)
Disaccharides: contain 2 carbon rings in their atoms (2 monosaccharides bonded together)
Polysaccharides: many monosaccharides bonded together (usually glucose)

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8
Q

Give examples of monosaccharides, disaccharides and polysaccharides and where we can find them.

A

Monosaccharides: glucose,fructose and galactose
Disaccharides: lactose,maltose and sucrose
Polysaccharides: glycogen,cellulose and starch

Monosaccharides: main source of energy for cells
Disaccharides: sucrose: the most simple table sugar + lactose is foud in milk and dairy products
Polysaccharides: cellulose is found in the cell walls of plant cells
glycogen is found in the cytoplasm of animal cells (energy storage)
starch is found in the cytoplasm of plant cells (energy storage)

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9
Q

What are lipids made up of and say if they are soluble or insoluble?

A

carbon,hydrogen and oxygen

insoluble (non-polar)

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10
Q

What is the monomer of lipids?
Explain its structure and draw a diagram.

A

Triglyceride: 1 glycerol molecule bonded to 3 fatty acid molecules.

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11
Q

What do we call many triglycerides joined together?

A

wax

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12
Q

Mention some examples of lipids.

A

oil,fat,phospholipids,cholesterol.

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13
Q

What are lipids mainly used for?

A

Insulation
energy
protection
storage
Lipids are usually found under the skin

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14
Q

What are proteins made up of and mention its monomer?

A

carbon,hydrogen,oxygen,nitrogen and sulfur.

amino acids

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15
Q

Mention some examples of protein.

A

keratin (makes up hair)
haemoglobin (found in red blood cells)

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16
Q

What is the smallest unit of an element?

A

atom

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17
Q

What is a molecule?

A

It is a group of atoms bonded together

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18
Q

What is a compound?

A

It is a group of different atoms bonded together

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19
Q

What is an atom made up of?

A

Nucleus

protons (positively charged)
neutrons (do not have no overall charge)
electrons (negatively charged)

An atom has the same number of neutrons as well as the same number of PROTONS

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20
Q

What is an ion?

A

An atom which is losing or gaining an electron

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21
Q

What happens to the atom if it loses or gains an electron?

A

If it loses an electron it becomes more positive,if it is gaining an electron its becoming more negative.

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22
Q

What is the difference between an ionic and a covalent bond?

A

An ionic bond: the attraction between oppositely charged ions forms an ionic bond

A covalent bond: the attraction between the sharing of electrons from the same atoms

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23
Q

Water is made up of 2 hydrogen atoms bonded to one oxygen atom forming hydrogen bonds that give water unique properties.

Mention some chemical properties of water

A

1) Water is a universal solvent ex: sugar or salt. (important chemical reactions taking place in animal or plant cells. This means it can dissolve a lot of substances in it especially polar substances.
2) High specific heat capacity: it can absorb heat without changing its temperature quickly
3) cohesion and adhesion forces: water molecules stick and attach ex: this allows water to be pulled up from the roots up into the leaves + allows insects to “walk on water due to the surface tension. (allows water to resist external force)
Cohesion: when water molecules stick to each other
Adhesion:when water molecules attach to other substances

4)Material carrier: carries sperm to the ova + 50% of the blood contains water to transfer substances
5) Lubricant: mucous is secreted externally in some animals like snails helping them to move
6)Has a metabolic role: chemical reactions need water to occur and are important in hydrolysis (break-down of large molecules using water)
7) Supportive functions such as : in the hydroskeleton of some organisms and it aids in the plants turgor pressure

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24
Q

What are simple and complex carbohydrates?

A

Simple: they can exist as simple sugars like glucose or fructose
Complex:more complex like starch and cellulose

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25
Q

Mention some foods which contain carbs

A

pasta,bread,rice and potatoes

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26
Q

The number of carbon atoms in monosaccharides can vary in 3 types. What are these called?

A

Pentoses 5
hexoses 6
septoses 7

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27
Q

What is the chemical formula of glucose?

A

C6H12O6

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28
Q

Draw the structure of a glucose molecule

A
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29
Q

True or false. Carbohydrates are broken down more rapidly than other nutrients

A

True

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30
Q

What is excess glucose converted to?

A

Glycogen and excess glycogen is converted to fat for storage

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31
Q

What are disaccharides made up of and what type of bond do we have between ?

A

Disaccharides are made up of 2 monosaccharides joined togther by a glycosidic linkage bond.

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32
Q

How are lactose,sucrose and maltose formed?

A

lactose:glucose + galactose
sucrose:glucose + fructose
maltose: glucose + glucose

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33
Q

Where is sucrose mainly found?

A

In plants and it is transported thorugh the phloem tissue+

sugar we normally buy in shops and found in sugar cane

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34
Q

What are hydrolysis and condensation reactions? + give an example

A

Hydrolysis is when: water is added to separate molecules

Condensation: water is removed to join molecules

Condensation :

glucose + glucose = maltose + WATER

Hydrolysis:

Maltose + WATER = glucose + glucose

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35
Q

Polysaccharides are complex carbohydrates.
Describe their structure.

A

Polysaccharides are made up of repeated monosaccharides joined together by glycosidic linkages. (usually glucose)

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36
Q

True or false
Polysaccharides are soluble.

A

False
INSOLUBLE

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37
Q

True or false
Polysaccharides can be branched or unbranched

A

True

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38
Q

Where is glycogen stored in the body?

A

The liver and the muscles

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39
Q

Mention some examples of lipids and ther consistency in room temperature

A

fats:solids at room temperature and oils are liquids at room temperature

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40
Q

When is the exception that lipids dissolve?

A

Only in acetone or alcohol

41
Q

What are the 2 types of lipids?

A

Simple and compound lipids

Simple lipids: fats and waxes
Compound lipids: phosopholipids,glycolipids and steroids

42
Q

What is the bond between the lipids called?

A

Ester linkage

43
Q

What are some sources where we can find lipids from?

A

butter, margarine and fried foods

44
Q

Where can we find lipids and mention some uses?

A

On the cell membrane
To protect delicate organs such as the heart and the kidneys
Sources of energy + insulation:in mammals, a layer of fat under the skin is present to keep warm

45
Q

What is a triglyceride made up of?

A

1 glycerol molecule and 3 fatty acid molecules

46
Q

Glycerol and fatty acids can be joined together to form a triglyceride.
What is this type of reaction called when small molecules are joined together to make large ones?

A

Anabolic and CONDENSATION REACTION

glycerol + 3 fatty acids = triglyceride + water (3 water molecules)

47
Q

Draw a triglyceride molecule
hydrolysis and condensation of tryglycerides

A
48
Q

Draw a glucose molecule
hydrolysis and condensation of disaccharides

A
49
Q

True or false.
Fats and oils contain a higher ammount of energy than proteins and carbohydrates

A

True

50
Q

What is the reason why fats are solids at room temperature and oils are liquids at room temperature?

A

Because fats are saturated with hydrogen making them more compact. No duble bonds are present

Oils are liquid because they contain unsaturated fatty acids with hydrogen

51
Q

Explain phospholipids

A

These are found on the cell membrane.

They contain a hydrophilic phosphate head and hydrophobic fatty acid tails

52
Q

Explain waxes

A

They are found in plants and annimals.

Waxes are similar to fats. The difference between waxes and fats is that waxes are linked to long chians of alcohol rather than a glycerol

53
Q

Explain steroids

A

Have 4 rings of carbons with functional groups attached
They can be either polar or non-polar dependng on the side groups

54
Q

Mention some importances of lipids.

A

Insulators
Vitamins A and D are lipids
And lipids can act as steroids (hormones like testosterone and oestrogeon)

55
Q

What is a protein?

A

A molecule composed of polymers of amino acids joined together by peptide bonds

56
Q

What is a polymer?

A

a large molecule composed of repeating units called monomers, which are covalently linked together

57
Q

What elements do proteins have?

A

carbon,oxygen,hydrogen,nitrogen and sulfur and sometimes phosphorus

58
Q

Where can we find proteins in food?

A

Meat,fish eggs and milk

59
Q

How many different types of amino acids are there?

A

20

60
Q

Describe the structure of amino acids

A

An amino acid contains an acidic carboxyl group (COOH) and an amino group (NH2) and a variable or an (R) group that differs amongst the 20 diffrent types of amino acids contributing to distinctive properties

61
Q

Draw an amino acid molecule

A
62
Q

Proteins are not stored in the body,however they are ingested. What happens to them and why?

A

Proteins have nitrogen and nitrogen is toxic in the body. The amino acids are deaminated in the liver.

The nitrogen part of the amino acid is removed and chnaged into urea where is it excreted by the kidneys

63
Q

What is the link between one amino acid and another called?

A

peptide bonds

64
Q

What do we call 2 amino acids joined together by a condensation reaction?

A

Dipeptide

65
Q

What do we call many amino acids joined together

A

Polypeptide chain

66
Q

What happens to proteins if the temperature exceeds 40 degrees ?

A

Proteins become denatured which can ruin its functions,because the molecule chnages shape

67
Q

Proteins can also be broken down using hydrolysis to form amino acids.
Condensation and hydrolysis reactions
Protein:Polypeptides: dipeptides,:amino acids

A
68
Q

Draw the formation + BREAKDOWN of a dipeptide
(DRAW BOTH THE CONDENSATION AND HYDROLYSIS OF A DIPEPTIDE)

A

The carboxyl group will link with the amino group of an amino acid to form a dipeptide (CONDENSATION)

69
Q

What is a tripeptide?

A

When 3 amino acids are bonded together by peptide bonds

70
Q

Mention the 4 types of protein structures

A

Primary
secondary
tertiary
quaterniary

71
Q

Describe and explain the 4 types of protein structure

A

Primary: depends on the sequence of amino acids which influences its biological functioning and structure

Secondary: a coiled structure when amino acids form hydrogen bonds between them: 3types: alpha helix (hair), beta pleated sheet (silk) and triple helix (the tail of a rat)

Tertiary structure: the amino acids are so close to each other that there is a further interaction between the R group

Quaternary: when 2 or more polypeptide chains interact together to obtain a structure and specific function ex: haemoglobin

72
Q

How can we further classify proteins?

A

Globular and fibrous

Globular: work in aqueous solutions

enzymes :catalyse organic reactions
messengers: to regulate biological processes (hormones)
Transporters of other molecules through membranes

Fibrous: insoluble (structure ex:keratin collagen tendons ( provide protection and support)

73
Q

True or false.

Most proteins are soluble

A

False
insoluble most of them (colloidal suspension)

74
Q

True or false
Proteins work in specific temperature and ph,and are denatured if extreme chnages in ph or temperature happen

A

True, because it causes the structure of the protein to be changed even if ph changes. The hydrogen bonds get destroyed

75
Q

What are essential and non-essential amino acids?

A

12 Non-essential amino acids: amino acids that can be synthesized by the body

8 Essential: amino acids that need to be consumed from the diet. (body cant make them)

76
Q

Why are proteins not stored in the body?

A

Because excess nitrogen is toxic in the body.

Excess amino acids are deaminated in the liver. Then they are removed and chnaged into urea wherby they wll be excreted by the kidneys

77
Q

What is the reason behind the solubility of carbohydrates, lipids, and proteins?

A

Because the solubility tends to decrease with increasing molecular size.

Ex: lipids are insoluble because they have long hydrocarbon chains making them hydrophobic

78
Q

What is the reason behind the differences in energy content in carbohydrates, proteins, and lipids?

A

All 3 nutrients provide a supply of energy.

However carbohydrates and proteins respire roughly the same ammount of energy when respired and broken down

Carbohydrates are the quickest to break

Fats they provide twice the ammount of energy as carbohydrates

79
Q

What is there inside the nucleus of a cell and what are their functions?

A

Chromosomes carry the genes that control the characteristics of the individual

80
Q

What are genes made up of?

A

DNA (deoxyribonucleic acid)

81
Q

What is DNA made up of?

A

Repeated units of nucleotides

82
Q

What is DNA?

A

It is a long polymer of repeated subunits called nucleotides

83
Q

What is a nucleotide made up of?

A

a phosphate group
5 carbon sugar (deoxyribose)
1 nitrogeneous base: adenine,thymine,guanine and cytosine

84
Q

What can we call the structure of a DNA molecule?

A

Double helix of 2 strands

85
Q

Draw a nucleotide

A
86
Q

How are the components of a nucleotide joined together?

A

Nitrogenous base is attached to carbon 1 of the deoxyribose

phosphate group attached to carbon 5 of the deoxyribose

A free hydroxyl group attached to carbon 3 of the deoxyribosde

87
Q

What do we call a chain with many nucleotides?

A

Polynucleotide

88
Q

What is the bond between nucleotides called?

A

Phosphodeister bond (strong covalent bonds)

89
Q

True or false?
DNA is made up of 2 strands of polynucleotides

A

True

90
Q

Where is the phosphodiester bond attached between the 2 nucleotides?

A

The phosphodeister bond attaches itself with carbon 3 and carbon 5 of the nucleotides

91
Q

What are the 2 diffrent sugars in DNA and RNA called?

A

DNA : deoxyribose
RNA: ribose

92
Q

What is a phosphodiester bond?

A

A group of strong covalent bonds between a phosphate group and two 5 carbon sugar

93
Q

How are the 2 strands joined together?

A

By the nitrogenous bases by hydrogen bonds

94
Q

True or false.
The 2 strands of polynucleotides are antiparallel

A

True

1 strand runs from the 5’ to te 3’
1 strand runs from the 3’ to the 5’

95
Q

Why are the nitrogenous bases complimentary to one another?

A

because adenine binds always with thymine
and cytosine always binds with guanine

96
Q

What are the proteins that make the DNA double helix shape which causes it to wrap up?

A

Histones

97
Q

Name the fat soluble vitamins

A

A,D and E

98
Q

Draw 2 polynucleotides bonded together

A
99
Q

Draw a water molecule

A