Chapter 1 : The Chemistry of Life Flashcards
(76 cards)
1
Q
What is an atom?
A
It is the smallest unit of matter that can take part in a chemical reaction
2
Q
What is a molecule?
A
Two or more atoms that combine with one another chemically
3
Q
What is an element?
A
A pure substance that is not made up of other similar substances
4
Q
What is a compound?
A
A pure substance that is made up of simpler substances (2 or more elements that are chemically combined)
5
Q
What is the formula for water?
A
H2O
- consists of hydrogen and oxygen
- made up of atoms of H and O
- 2 hydrogen atoms and 1 oxygen atom
6
Q
What are the 7 basic characteristics of life?
A
- nutrition
- response to stimuli
- growth
- reproduction
- respiration
- excretion
- locomotion
7
Q
What is a cell?
A
The smallest unit of life that contains cellular inclusions (organelles)
8
Q
What is a tissue?
A
A group of similarly differentiated cells that perform a common function
9
Q
What is an organ?
A
A group of differentiated tissues, each of which performs its own function, but together performs a common function
10
Q
What are the two groups that chemical compounds are divided into?
A
Inorganic compounds and organic compounds
11
Q
What are inorganic compounds?
A
It is chemical compounds that do not contain the element carbon and are not produced by living organisms
- eg) water, mineral salts, gases
12
Q
What are organic compounds?
A
It is chemical compounds that contain the element carbon and are produced by living organisms
- composed of carbon, hydrogen, oxygen, and also sometimes nitrogen, phosphorus, sulphur
- eg) carbohydrates, lipids, proteins, nucleic acids and vitamins
13
Q
Water
A
- most important inorganic compound for living organisms
- no water, no life
- 75% of plant and animal bodies
14
Q
What are the different functions of water in living organisms?
A
- Solvent
- Medium in which chemical reactions occur
- Reagent during hydrolysis
- Transporting agent
- Lubricant
- Regulates body temperature
- Gives shape and rigidity
15
Q
Solvent
A
- solvent for inorganic and organic
- hydrophyllic (dissolves in water) (eg. minerals dissolve in water for roots to absorb)
- hydrophobic (does not dissolve in water) (eg. fats and oils)
16
Q
Medium in which chemical reactions occur
A
- all chemical reactions in living organisms occur in water
17
Q
Reagent during hydrolysis
A
- water breaks polymers down into their monomers
18
Q
Transporting agent
A
- digested nutrients, metabolic waste products, gases, mineral salts are transported in water
19
Q
Lubricant
A
- makes chewing and swallowing easier
- aids the movement of food through the rest of the alimentary canal
- watery fluids surround eyeballs and joints to prevent friction
20
Q
Regulates body temperature
A
- body loses water through sweat, which evaporates and cools body
21
Q
Gives shape and rigidity
A
- animals like jellyfish have hydrostatic skeletons that gives shape
- water in vacuoles of plant cells cause internal pressure that pushes against cell wall (turgor pressure)
22
Q
Mineral salts
A
- needed and absorbed by living organisms
- plant roots absorb from soil
- humans and animals obtain from food
23
Q
What are macro elements?
A
Mineral salts that are needed in large quantities (everyday) (plants : soil)
24
Q
What are micro elements?
A
Mineral salts that are needed in smaller quantities (animals : food)
25
What are some macro elements?
- Calcium
- Phosphorus
- Sodium
- Potassium
26
Calcium
- builds strong teeth and bones
- necessary for blood coagulation
- Humans : rickets
- Plants : weak plant growth
27
Phosphorus
- component of ATP, DNA, RNA
- part of phospholipids in cell membranes
- Humans : seldom occurs
- Plants : stunted plant growth
28
Sodium
- important for maintaining water balance in body
- controls rhythm of heart
- Humans : muscle cramps
- Plants : unknown
29
Potassium
- important for maintaining water balance in body
- controls heart rhythm
- Humans : seldom occurs
- Plants : yellow and brown leaf margins
30
What are the micro elements?
- Iron
- Iodine
31
Iron
- helps to form haemoglobin that transports O2 in blood
- helps to form chlorophyll molecules
- Humans : anaemia
- Plants : chlorosis
32
Iodine
- component of hormone thyroxin
- Humans : goitre
33
What are some mineral compounds?
- Phosphates (main source of P in plants)
- Nitrates (main source of, needed for protein synthesis)
34
Carbohydrates
- made up of C, H, O
- ratio of H and O is 2:1
35
What are carbohydrates made up of?
- made up of ring shaped units called saccharides
- divided into 3 groups according to number of saccharides
- monosaccharides (sugar)
- disaccharides (sugar)
- polysaccharides (not sugar)
36
Monosaccharides
(single sugar)
- 3 types
- glucose, fructose, galactose
(glucose is the basic building block of all carbohydrates)
37
Disaccharides
(double sugars)
- when two monos are joined
- one water molecules is removed to form a di
- known as condensation reaction
- 3 types
- maltose, sucrose, lactose
38
Glucose + Glucose =
Maltose + H2O
39
Glucose + Fructose =
Sucrose + H2O
40
Glucose + Galactose =
Lactose + H2O
41
Polysaccharides
- long chains of mono that bind one another
- 3 types
- starch, glycogen, cellulose
42
What is starch?
- form in which glucose is stored in plant
43
What is glycogen?
- form which excess glucose is stored in liver and skeletal muscles of humans and animals
- when energy is needed, transfers back to glucose
44
What is cellulose?
- forms structural component of plant cell walls
45
What is the importance of carbohydrates in animals and plants?
- source of energy
- source of reserve energy
- structural component
46
What can we use to test for the presence of glucose?
Benedict's solution
- it is a deep blue liquid that indicates presence of mono and di
- if blue = no glucose
- orange/red = gluscose
47
Testing for starch
- use yellow-brown iodine
- turns blue/black = starch present
48
Lipids
- made up of the same 3 elements as carbohydrates
- C, H, O
- ratio H:O, far greater than 2:1
- contain double the number of H and O
49
What does lipids consist of?
- glycerol
- fatty acids
(different types of lipids contain different fatty acid molecules)
50
What are the characteristics of lipids?
- insoluble in water
- soluble in ether and alcohol
- hydrophobic
51
2 types of lipids
- saturated fats
- unsaturated fats
52
What are saturated fats?
- mainly derived from animals
- solid at room temperature
- eg) butter
53
What are unsaturated fats?
- mainly derived from plants (olive oil)
- liquid at room temperature (oils)
- used by body to synthesize cholesterol
54
What is cholesterol?
It is a white, wax-like substance that forms part of cell membranes and hormones
- formed by excessive intake of saturated fats in the blood
- causes fatty deposits (plaque) in arteries, and narrows them
- narrowing known as atherosclerosis
55
What is the importance of lipids in animals and plants?
- source of reserve energy
- insulating material
- shock absorption
- structural component of cell membranes
- waterproofing
- absorption of vitamins (A,D,E,K)
- source of water
56
How do we know when fats are present during a test?
When there is a translucent greasy spot left on the filter paper
57
What are proteins?
It is a polymer with amino acids as monomers
58
What are amino acids made up of?
- C, H, O, N
- some amino acids have P, S, Fe present
- 20 different amino acids
59
What does the sequence of amino acids determine?
It determines the type of protein
60
What is a peptide bond?
It is a bond/link formed between 2 amino acids
61
What are the different types of peptide bonds?
- Dipeptide = 2
- Tripeptide = 3
- Polypeptide = long chain
- Protein = 51+ amino acids
- each protein has own shape, it determines the function that must be performed
62
Why are proteins sensitive to temperature and pH?
They are sensitive as they will denature at high temperatures and will lose their shape and function
63
What is the importance of proteins in animals and plants?
- structural component of protoplasm
- building materials
- structural component of cell membranes
- play a role in the permeability of cell membranes
- source of reserve energy
- hormones regulate processes in the body
- haemoglobin transports O2 and CO2 in blood
- protect the body against disease
- chromosomes carry hereditary material
- act as buffers
- enzymes control metabolic processes in body
64
How can we test for proteins?
- biuret test
- blue - no protein present
- purple - protein present
65
What are enzymes?
It is a biological catalyst that acceleratse chemical reactions inside living cells and lowers the activation energy without itself being changed by the reaction
66
What are reactions called that take place in living cells called?
Metabolic reactions
67
2 types of metabolic reactions
- anabolic
- catabolic
68
Anabolic reaction
- when a complex molecule is built up from simple molecules
- energy required
69
Catabolic reaction
- when a complex molecule is broken down into simple molecules
- energy released
70
Some digestive enzymes
maltose + water = maltase = glucose + glucose
sucrose + water = sucrase = glucose + fructose
lactose + water = lactase = glucose + galactose
starch + water = amylase = maltose
lipid + water = lipase = glycerol and 3 fatty acids
proteins + water = protease = smaller polypeptides
71
Nucleic acids
- made up of elements C, H, O, N, P
72
2 types of nucleic acids
- DNA
- RNA
73
DNA
- found in nucleus of cell
- carries hereditary characteristics and controls structure and function of cell
74
RNA
- found in nucleus and cytoplasm
- forms part of ribosomes
- plays a role in protein synthesis to ensure amino acids bind together
75
Vitamins
- essential for normal metabolism, growth and development of body
- needed in smaller quantities
- produced by plants
76
2 types of vitamins
- water-soluble (B,C)
- fat-soluble (A,D,E,K)
