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Biology > Topic 1 Molecules, Transport and Health > Flashcards

Topic 1 Molecules, Transport and Health Flashcards

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1
Q

Why water is a polar molecule?

A

Because the electrons are held closer to the oxygen atom than to the hydrogen atoms

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2
Q

Why water has a relatively high boiling and melting point compared with other substances that have molecules of a similar size.

A

Because it takes a lot of energy to break all the hydrogen bonds

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3
Q

Where are hydrogen bond important?

A

In protein structure and in the structure and functioning of DNA

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4
Q

What does cohesive mean? (water is cohesive)

A

This means that the forces between the molecules stick together. This is important for the movement of water from the roots to the leaves of plants.

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5
Q

What does adhesive mean? (water is adhesive)

A

They are attracted to other different molecules. This is important in plant transport and in surface tension

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6
Q

Why water is slow to absorb and release heat?

A

it has specific heat capacity
Because hydrogen bonds between molecules need a lot of energy to separate them

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7
Q

Why water has a very high surface tension?

A

Because the attraction between the water molecules, including hydrogen bonds, is greater that the attraction between water molecules and the air.

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8
Q

What is dipole?

A

The separation of charge in a molecule when electrons in covalent bonds are not evenly shared

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9
Q

What is polar molecule?

A

A molecule containing a dipole

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10
Q

What is dissociation?

A

Splitting of a molecule into smaller molecules, atoms, or ions, especially by a reversible process

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11
Q

What are hydrogen bonds?

A

Weak electrostatic intermolecular bonds formed between polar molecules containing at least one hydrogen atom

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12
Q

What is monomer?

A

A small molecule that is a single unit of a larger molecule (Polymer)

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13
Q

What is polymer?

A

A long-chain molecule made up of many smaller, repeating monomers joined by chemical bonds

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14
Q

What is macromolecule?

A

A very large molecule ( often formed by polymerisation)

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15
Q

What are carbohydrates?

A

Carbohydrates are important in cells as an energy storage in animals and form an important part of cell wall in plants

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16
Q

What are the best known carbohydrates?

A

Sugars and starch

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17
Q

What is glucose?

A

A hexose sugar and it is used as a fuel by the cells of our bodies.

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18
Q

What does the basic structure of carbohydrates consist of?

A

Consists of carbon, hydrogen and oxygen

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19
Q

What are the main groups of carbohydrates?

A

Monosaccharides, disaccharides and polysaccharides

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20
Q

What are monosaccharides?

A

They are simple sugars

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21
Q

What are triose sugars?

A

A sugar with three carbon atoms
Important in mitochondria, where respiration process breaks down glucose into triose sugars.

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22
Q

What are pentose sugars?

A

A sugar with five carbon atoms
Ribose and Deoxyribose are important in the nucleic acids DNA and RNA, which make up the genetic material.

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23
Q

What are hexose sugars?

A

A sugar with six carbon atoms.
Best known monosaccharides, often taste sweet and include glucose, galactose and fructose.

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24
Q

What are isomers?

A

Molecules that have the same chemical formula, but different molecular structures.

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25
What is disaccharide?
A sugar made up of two monosaccharides joined by glycosidic bonds
26
What is condensation reaction?
A reaction in which molecules of water is removed from reacting molecules as a bond is formed between them
27
How does disaccharide form?
Two monosaccharides join in a condensation reaction and glycosidic bond is formed between them.
28
How sucrose is made?
By joining glucose and fructose
29
How lactose is made?
By joining glucose and galactose
30
How maltose is made?
By joining two glucose
31
What are the three common disaccharides?
Sucrose, lactose, maltose
32
What are the most complex carbohydrates?
Polysaccharides
33
What is polysaccharide?
A polymer consisting of long chains of monosaccharides joined by glycosidic bonds
34
What are oligosaccharides?
Molecules with between 3 and 10 sugar units
35
How does glycosidic bond is split between two glucose units?
By hydrolysis
36
What is hydrolysis?
A reaction in which bonds are broken by addition of a molecule of water.
37
What is ATP?
The molecule that acts as a universal energy supply molecule in all cells.
38
What is the structure of polysaccharides?
Their structure make them ideal as energy storage molecules within a cell: They form very compact molecules (take up little space) They are physically and chemically inactive (do not interfere with other functions of the cell) They are not very soluble in water, (so no effect on water potential within a cell and cause no osmosis water movements)
39
What is starch?
Example of polysaccharide, energy storage in plants. The sugars produced by photosynthesis are rapidly converted into starch ( which can be broken down to release glucose)
40
What does starch consist of?
amylose and amylopectin
41
What is amylose?
An unbranched polymer that forms spiral ( makes it more compact for storage)
42
What is amylopectin?
A branched polymer that forms long chains
43
What is glycogen?
The only carbohydrate energy store found in animals. Has more side branches than starch. ( can be broken down very rapidly)
44
What are lipids?
a large family of organic molecules that are important in cell membranes as an energy store in many organisms.
45
What are the organisms that have lipids as an energy store?
triglycerides, phospholipids, steroids
46
What is the state of fats and oils in room temperature?
Oils are liquids, fats are solids.
47
What are the chemical elements that all lipid molecules contain?
Carbon, hydrogen, oxygen
48
What organic chemical substances do fats and oils contain?
Fatty acids and glycerol
49
What are ester bonds?
Bonds formed in a condensation reaction (esterification) between the carboxyl group of a fatty acid and one of the hydroxyl groups of glycerol.
50
What is esterification?
The process by which ester bonds are made
51
What are fatty acids?
organic acids with a long hydrocarbon chain
52
What is the important component of triglycerides?
Glycerol
53
When triglyceride is made?
When glycerol combines with three fatty acids
54
What is saturated fatty acid?
A fatty acid in which each carbon atom is joined to the next to it in the hydrocarbon chain by a single covalent bond
55
What is unsaturated fatty acid?
a fatty acid in which the carbon atoms in the hydrocarbon chain have one or more double covalent bonds in them
56
What is monounsaturated fatty acid?
A fatty acid with only one double covalent bond between carbon atoms
57
What is polyunsaturated fatty acid?
a fatty acid with two or more double covalent bonds between carbon atoms
58
What do proteins make?
Hair, skin, nails, the enzymes needed for metabolism and digestion and many of the hormones that control the different body systems.
59
What is haemoglobin?
A red pigment that carries oxygen
60
What are amino acids?
the building blocks of proteins consisting of an amino group (-NH2) and a carboxyl group (-COOH) attached to a carbon atom and an R group that varies between amino acids
61
What are proteins?
a group of macromolecules made up of many small monomer units called amino acids joined together by condensation reactions.
62
What do amino acids do to produce proteins?
they combine in long chains
63
How the way the amino acid interacts with others is affected?
By the structure of the R group. This depend on whether the R group is polar or not, and these interactions affect the tertiary structure of protein formed.
64
How do proteins form from amino acids?
Amino acids join by a reaction between the amino group of one amino acid, and the carboxyl group of another. They join in a condensation reaction and a molecule of water is released. A peptide bond is formed when amino acids join, and a dipeptide is the result. The R group is not involved in this reaction.
65
What is dipeptide?
two amino acids joined by a peptide bond
66
What is polypeptide?
a long chain of amino acids joined by peptide bonds
67
What do bonds in the 3D structure of the protein depend on?
they depend on the atoms in the R group and include hydrogen bonds, disulfide bonds and ionic bonds.
68
How are hydrogen bonds important ?
They are important in the folding and coiling of polypeptide chains. Hydrogen bonds break easily and reform if pH or temperature conditions change
69
How do disulfide bonds form?
they form when two cysteine molecules are close together in the structure of a polypeptide.
70
How are disulfide bonds important?
They are important for holding the folded polypeptide chains in place
71
How ionic bonds can form?
They form between some of the strongly positive and negative amino acids side chains.
72
What is the primary structure of a protein?
is the sequence of amino acids that make up the polypeptide chain, held together by peptide bonds.
73
What is the secondary structure of a protein?
is the arrangement of the polypeptide chain into a regular, repeating 3D structure, held together by hydrogen bonds.
74
What is tertiary structure of a protein?
The 3D folding of the secondary structure. The amino acid chain (a-helix and b-pleated sheets ) is folded into complicated shapes. Hydrogen bonds, disulfide bonds and ionic bonds between R groups of nearby amino acids hold these 3D shapes in place.
75
What is the quaternary structure of a protein?
The 3D arrangement of more than one tertiary polypeptide.
76
How can changes in conditions (temperature or pH) affect the bonds that keep 3D shapes of proteins in place?
can cause the bonds to break, resulting in the loss of the 3D shape of protein. This is called denaturation. this can cause proteins such as enzymes to stop working properly.
77
What is denaturation?
The loss of the 3D shape of a protein
78
What are fibrous proteins?
Proteins that have long, parallel polypeptide chains with occasional cross-linkages that produce fibres; they have little tertiary structure. They are insoluble in water and very tough
79
What are globular proteins?
Large proteins with complex tertiary and sometimes quaternary structures , folded into spherical shapes
80
What is collagen?
A strong fibrous protein with a triple helix structure
81
What is hydrophobic?
a substance that tends to repel water and that will not mix with or dissolve in water
82
What is hydrophilic?
a substance with an affinity for water that will readily dissolve in or mix with water
83
What is colloid?
a suspension of molecules that are not fully dissolved
84
What are conjugated proteins?
protein molecules joined with another molecule called a prosthetic group
85
What is diffusion?
One of the main ways substances move into and out of cells. It is the free movement of particles in a liquid or a gas down a concentration gradient ( from high to low)
86
Why single-celled organisms and very small multicellular organisms do not need specialised transport systems?
Because diffusion is enough to supply their needs
87
What is the key factor that determines whether diffusion will allow substances to move in and out of all the cells rapidly enough?
the surface area to volume ratio of an organism
88
What is concentration gradient?
The change in the concentration of solutes present in a solution between two regions, this typically means across a cell membrane.
89
What is mass transport system?
An arrangement of structures by which substances are transported in the flow of a fluid with a mechanism for moving it around the body.
90
What is single circulation system?
A circulation in which the heart pumps the blood to the organs of gas exchange and the blood then travels on around the body before returning to the heart.
91
What is double circulation system?
A circulation that involves two separate circuits, one of deoxygenated blood flowing from the heart to the gas exchange to be oxygenated before returning to the heart, and one of oxygenated blood leaving the heart and flowing around the body, returning as deoxygenated blood to the heart.
92
What are the two separate circulation systems in double circulation?
The systemic circulation and the pulmonary circulation.
93
What does systemic circulation do?
Carries oxygenated blood from the heart to the cells of the body where oxygen is used
94
What does pulmonary circulation do?
Carries deoxygenated blood from heart to the lungs to be oxygenated and then carries the oxygenated blood back to the heart.
95
What is the purpose of the separate circuits of a double circulatory system?
They ensure that the oxygenated and deoxygenated blood cannot mix, so the tissues receive as much oxygen as possible.

Biology (4 decks)

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