1b - more biological molecules Flashcards
(78 cards)
1
Q
what are DNA and RNA both types of
A
nucleic acid
2
Q
where are DNA and RNA found
A
in all living cells
3
Q
what do both DNA and RNA do
A
carry information
4
Q
what is DNA used to do
A
store genetic information
5
Q
what is genetic information
A
all the instructions an organism needs to grow and develop
6
Q
What does RNA do
A
transfers genetic information from the DNA to the ribosomes
7
Q
what are ribosomes
A
the bodys ‘protein factories’ made from RNA and proteins
8
Q
what do ribosomes do
A
they read the RNA to make polypeptides (proteins) in a process called translation.
9
Q
what is a nucleotide
A
a type of biological molecules
10
Q
what is a nucleotide made from
A
- a pentose sugar
- a nitrogen containing organic base
- a phosphate group
11
Q
why are nucleotides important
A
they are the monomers that make up DNA and RNA
12
Q
what is the pentose sugar in a DNA nucleotide called
A
deoxyribosew
13
Q
hat does each DNA nucleotide have
A
the same sugar and a phasphate group which can vary for each nucleotide
14
Q
what are the 4 possible bases in a DNA nucleotide
A
- adenine
- thymine
- cytosine
- guanine
15
Q
what sugar is in RNA nucleotides
A
a ribose sugar
16
Q
what is in an RNA nucleotide
A
a phosphate group and one of four different bases
17
Q
what are the 4 possible bases in an RNA nucleotide
A
the same as a DNA nucleotide except uracil replaces Thymine
18
Q
what is a polynucleotide
A
a polymer of nucleotides
- both RNA and DNA form polynucleotides
19
Q
how do nucleotides join up
A
via a condensation reaction between the phosphate group of one nucleotide and the sugar of another forming a phosophodiester bond
20
Q
what is a sugar phosphate backbone
A
the chain of sugars and phosphates
21
Q
DNA structure
A
made up of two polynucleotide chains in a double helix structure
22
Q
how are two DNA polynucleotide strands joined together
A
by hydrogen bonding between the bases
23
Q
what is complementary base pairing
A
each base can only join with one particular partner
24
Q
what are the base pairs
A
adenine and thymine, cytosine and guanine
25
how many hydrogen bonds form between A and T
two
26
how many hydrogen bonds form between C and G
three
27
what forms the DNA double helix
two antiparallel polynucleotide strands twisted
28
when was DNA first observed
in the 1800s
29
RNA structure
made from a single polynucleotide chain, much shorter than most DNA polynucleotides
30
How does Dna replicate
by semiu-conservative replication
31
why does DNA replicate itself before cell division
so that each new cell has the full amount of DNA
32
why is this method called Semi-conservative replication
because half of the strands in each new DNA molecule are from the original DNA molecule. meaning there is genetic continuity between generations of cells
33
step 1 of DNA replication
DNA helicase breaks the hydrogen bonds between bases on the two polynucleotide DNA strands. this makes the helix unwind to form two single strands
34
step 2 of DNA replication
each original single strand acts as a template for a new strand. complementary base pairing means that free floating DNA nucleotides are attracted to their complementary exposed bases on each template strant
35
step 3 of DNA replication
condensation reactions join the nucleotides of the new stands together, catalysed by the enzyme DNA polymerase. hydrogen bond form between the bases on the original and new strands
36
step 4 of DNA replication
each new DNA molecule contains one strand from the original DNA molecule and one new strand
37
how does DNA polymerase move
In opposite ways along antiparallel DNA strands
38
what is different about each end of a DNA strand
slightly different in its structure
one end is called he 3' end and one end is called the 5' endh
39
how do the strands run in a DNA helix
in opposite directions, they are antiparallel
40
what is the active site of DNA polymerase complementary to
the 3' end of the newly forming DNA strand, so the enzyme can only add nucleotides to the strand at the 3' end
41
how does DNA polymerase form new strands
the new strand is made in a 5' to 3' direction, the DNA polymerase working on one of the template strands moves in the opposite direction to the DNA polymerase working on the other template strand
42
what % of cell contents does water make up
80%
43
water as a metabolite
it is a metabolite in loads of important metabolic reactions including condensation and hydrolysis reactions
44
water as a solvent
some substances dissolve in it. most metabolic reaactions take place in solution so water is essential
45
water - temperature control
has a high latent heat of vaporisation and a high specific heat capacity
46
water molecules - cohesive
they stick together which helps water transport in plants as well as transport in other organisms
47
what kind of structure are water molecules
simple structures
48
structure of water
one atom of oxygen, joined to two atoms of hydrogen by shared electrons
49
why are the other sides of the hydrogen atoms left with a slight positive charge
because the shared negative hydrogen electrons are pulled towards the oxygen atoms
50
why does the oxygen atom have a slight negative charge
the unshared negative electrons
51
what kind of molecule is water
a polar molecule - it has a partial negative charge on one side and a partial postive charge on the other
52
hydrogen bonding
the slightly negatively-charged oxygen atoms attract the slightly positively charged hydrogen atoms of other water molecules
53
why is water an improtant metabolite
1. many metabolic reactions involve a condensation or hydrolysis reaction
2. a hydrolysis reaction requires a molecules of water to break a bond and a condensation reaction releases a molecule of water as a new bond is formed
54
water has a high latent heat of vaporisation
1. it takes a lot of energy to break the hydrogen bonds between water molecules
2. a lot of energy is used up when water vapourises
3. useful for living organisms because it means they can use water loss through evaporation to cool down without losing to much water
55
water can buffer changes in temperature
the hydrogen bonds can absorb alot of energy
2. so water has a high specific heat capacity aka it takes a lot of eneryg to heat up
3. useful as it means water doesnt experience rapid temperature changes, inside organisms remains a fairly stable temp helping to maintain a constant internal body temperature
56
water is a good solvent
because water is polar the postive end of a water molecule will be attracted to the negative ion and the negative end of the water molecule will be attracted to the positive ion meaning the ions will get totally surounded by water molecules (dissolve)
57
strong cohesion between water molecules
water molecules are very cohesive because they are polar
helps water to flow making it great for transporting substances
high surface tension when it comes into contact with air
58
ATP
immediate source of energy in a cell
59
respiration
the process of plants and animals releasing energy from glucose
60
process of respiration
- energy released from glucose is used to make ATP
- ATP diffuses to the parts of the cell that need energy
61
what is ATP made from
the nucleotide base adenine combined with a ribose sugar and three phosphate groups
62
how is the enegy in atp stored
in high energy bonds between the phosophate groups
63
how is the energy in atp released
via hydrolysis reactions
64
what does atp stand for
adenosine triphosphate
65
what happens when energy is needed by a cell
atp is broken down into adp via hydrolysis reaction catalysed by the enzyme atp hydrolase
66
how can atp be resynthesised
in a condensation reaction between adp and p during both repsiration and photosynthesis catalysed by the enzyme atp synthase
67
what is an ion
an atom or group of atoms that have an electric charge
68
what is an ion with a postive charge called
a cation
69
what is an ion with a negative charge called
an anion
70
what is an inorganic ion
an ion that doesnt contain carbon
71
what are the inorganic ions in the cytoplasms cells used for
each ion has a specific role depending on its proporties. determines whether its found in high or low concentrations
72
haemoglobin
a large protein that carries oxygen around the body in the red blood cells
73
what is haemoglobin made up of
four different polypeptide chains each with an iron ion in the centre
74
what does iron do in haemoglobin
binds the oxygen in haemoglobin
75
what happens when oxygen is bound in haemoglobin
the iron 2+ ion temporarily becomes an iron 3+ ion until oxygen is released
76
what do hydrogen ions do
determine the pH as pH is calculated based on the concentration of hydrogen ions in the environment. the more H+ present the lower the pH
77
what do sodium ions do
help transport glucose and amino acids across membranes through co transport
78
what do phosphate ions do
they are an essential component of ATP and DNA
the bonds between phosphate groups store energy in atp
phosophate groups in DNA and RNA alow nucleotides to join up to form polynucleotides
