DNA: The code of life Flashcards
1
Q
Where do cells carry out various cellular activities?
A
Within the cytoplasm
2
Q
What is the main thing that happens during cellular activities?
A
Useful substances such as water and nutrients enter the cell from the outside
3
Q
What is removed from the cells?
A
Waste products
4
Q
What is the cytoplasm?
A
A water solution that consists of a mixture of substances .
5
Q
What substances does the cytoplasm contain?
A
dissolved salts gases proteins carbohydrates suspended fats
6
Q
What are suspended in the cytoplasm of a cell?
A
cell organelles
7
Q
What are ribosomes?
A
small, granular organelles
occur in rows on the surface of rough ER (endoplasmic reticulum) or in groups in the cytoplasm.
8
Q
What is a ribosome made of?
A
RNA and Protein
9
Q
What is the site of protein synthesis?
A
a ribosome
10
Q
What is the control centre of the cell?
A
The nucleus
11
Q
What activities does the nucleus control?
A
synthesis of proteins
transmits hereditary information into daughter cells during cell division
12
Q
What surrounds the nucleus?
A
a double nuclear membrane with nuclear pores
13
Q
What do the pores in the double nuclear membrane surrounding the nucleus do?
A
allow substances to move between the nucleus and the cytoplasm
14
Q
What is nucleoplasm?
A
jelly-like substance that fills the nucleus
15
Q
What does the chromatin network form during cell division?
A
chromosomes
16
Q
What is the nucleolus?
A
the round thing inside the nucleus
17
Q
What is the nucleolus composed of?
A
protein and RNA
18
Q
What does RNA stand for?
A
ribonucleic acid
19
Q
What is the stored RNA (in the nucleolus) involved in?
A
synthesis of proteins within the cell
20
Q
What is the membrane which surrounds an animal cell called?
A
cell membrane
21
Q
What are biological molecules that are essential for all life forms?
A
nucleic acids
22
Q
What do nucleic acids include?
A
DNA and RNA
23
Q
What does DNA stand for?
A
deoxyribonucleic acid
24
Q
What does DNA make up?
A
the genes located on chromosomes
25
What is formed in the nucleus but funcitons in the cytoplasm?
RNA
26
Where is RNA formed?
in the nucleus
27
What are nucleic acids?
polymers
28
What are polymers made of?
smaller, similar building blocks called monomers
29
What are the monomers of nucleic acids called?
nucleotides
30
What three parts is one nucleotide made up of?
P (phosphate group)
S (sugar)
N (nitrogenous base)
31
Where does most DNA occur?
In the nucleus
32
What is DNA that occurs in the nucleus called?
nuclear DNA
33
What is DNA would around?
protein molecules called histones
34
What is a histone?
the protein molecule that DNA is wound around
35
What forms a chromosome that makes up part of the chromatin network?
DNA and histones
36
Does any DNA occur outside the nucleus?
Yes. But only small amounts
37
What is DNA that occurs outside the nucleus called?
extra-nuclear DNA
38
Where does extra-nuclear DNA occur?
outside the nucleus:
In the mitochondria
In the chloroplast
39
What is DNA that occurs in the mitochondria called?
mitochondrial DNA
| This is extra-nuclear DNA
40
What is DNA that occurs in the chloroplast called?
Chloroplast DNA
| This is extra-nuclear DNA
41
Who took many X-ray photographs of DNA?
Rosalind Franklin
| These showed the double helix structure of DNA but she did not realise it
42
Who showed one of the X-ray photographs to Watson and Crick without Franklin's permission?
Maurice Wilkins
43
Who formulated the double-helix structure of DNA with the aid of a 3D model?
Watson and Crick
44
What is the journal that Watson and Crick published their findings in?
Nature
| This happened while they were working at the Cavendish Institute in Cambridge
45
What is the journal that Franklin and Gosling published a paper in?
Nature
46
What was the name of the journal that Maurice Wilkins published a paper in?
Nature
47
Which three parties all published a paper in the same issue of Nature all showing the double helix structure of DNA?
Watson and Crick
Franklin and Gosling
Wilkins
48
Who received a Nobel Prize for discovering the molecular structure of DNA?
Watson and Crick in 1962
49
When was Nature published which showed the structure of DNA by three different parties?
1953
50
Who was the first director of the Human Genome Project?
Watson
51
When did scientists first map the human genome in its entirety?
2003
52
What is the structure of DNA?
It is a double-stranded molecule that forms a double helix
53
What type of sugar does DNA contain?
Deoxyribose sugar
54
What are the four types of nitrogenous bases that DNA contains?
adenine
thymine
guanine
cytosine
55
What forms pairs in the DNA molecule?
nitrogenous bases
56
What type of bonds hold the nitrogenous bases found in DNA molecules?
weak hydrogen bonds
57
What forms a long chain in a DNA molecule?
The sugar and phosphate group
58
What is often regarded as the 'backbone' of a DNA molecule?
The long chain of sugar and phosphate group
59
At what angle are the nitrogenous bases attached to the 'backbone chain' of the DNA molecule?
At right angles
60
What are the main functions of DNA?
- contains the genetic instructions to make different proteins in the body
- maintains the structure of the chromosomes
- regulates the function of genes
- regulates protein synthesis
- enables hereditary material to be passed from parent to offspring
61
What are a good sample to extract DNA from?
Peas or onions
62
How do you extract DNA from a sample?
- break open cells using dishwashing liquid and salt
- Add meat tenderiser
- purify DNA with ice-cold alcohol
- DNA will float to top
63
Why must you use dishwashing liquid and salt to extract DNA?
This breaks up the cells which allows you to get to the DNA
64
Why must you add meat tenderiser to extract DNA from a sample?
This contains protease enzymes which breaks down the proteins around the DNA
65
Why do you purify the DNA with ice-cold alcohol when extracting DNA from a sample?
DNA is insoluble in alcohol so it floats to the top
66
What is DNA replication?
The process whereby DNA makes an identical copy of itself
67
Where does DNA replication take place?
In the nucleus
68
When does DNA replication take place?
During interphase - just before cell division
69
What are all processes of DNA replication controlled by?
All stages of the process are controlled by specific enzymes
70
Explain, in five brief steps, how DNA replication takes place
- unwinding
- separation
- assembly
- bonding
- rewinding
71
What does a DNA molecule look like when it has unwound?
Like a ladder
72
How do the nitrogenous bases separate during the DNA replication process?
the weak hydrogen bonds break
| Enzyme used: DNA helicase
73
What enzyme is used when the nitrogenous bases separate in the process of DNA replication?
DNA helicase
74
Does the whole length of the DNA strand separate during DNA replication?
Yes
75
What does each strand of DNA become once separated in the DNA replication process?
A template to form a new strand on each
76
Where do free DNA nucleotides come from which attach to the exposed complementary bases on the DNA strands during the DNA replication process?
From the nucleoplasm
77
Each new DNA molecule consists of one ___ strand and one ___ strand
original and new
78
Are the two DNA molecules produced in the DNA replication process identical?
Yes
79
What is the shape of a wound up DNA ladder-shaped molecule?
double helix
80
What enzyme is involved in the assembly of the two identical DNA molecules formed during DNA replication?
DNA polymerase
81
What enzyme is involved in the winding up of the two new DNA ladder-shaped molecules formed during DNA replication?
DNA polymerase
82
Why is DNA replication important?
- Each daughter cell produced during meiosis has identical genetic make-up to the parent cell.
- Ensures that the number of chromosomes in each daughter cell is the same as in the parent cell.
- Ensures that genetic information is transferred from one generation to the next.
83
Define DNA profiling
The use of a person's DNA to identify them or to trace the genetic relationships between people
84
What two things can be done with DNA profiling?
identify people
| trace genetic relationships
85
Where is DNA extracted from in DNA profiling?
From a body tissue or body fluid (e.g. blood, skin, saliva)
86
What is DNA profiling also known as?
DNA fingerprinting
87
What does a genetic profile (genetic fingerprint) look like?
A pattern of black bars left on X-ray film that shows the unique DNA of the person
88
What diseases can DNA profiling be used to detect?
Genetic disorders such as:
haemophilia
sickle cell anaemia
89
What can be used to confirm a person as a suspect in a crime?
DNA evidence
90
In what situations can DNA profiling (or fingerprinting) be used to identify relatives?
- To determine the father of a child
- To help parents find a missing child
- To identify a body that cannot be identified after death
91
What are some reasons that people have to not rely on DNA fingerprinting (or DNA profiling)
- only short DNA strands are used
- chance of human error
- expensive
- some DNA labs may not follow correct procedure
- DNA profiling could reveal confidential info (HIV status)
92
What type of acid is RNA?
A nucleic acid
93
What does RNA do?
carries genetic information from DNA in nucleus to parts of the cell where it is needed
94
What does RNA play a vital role in?
protein synthesis
95
Is RNA more stable that DNA?
No. RNA is less stable than DNA and breaks down easily.
96
What happens once RNA has completed its function (normally in protein synthesis)?
It breaks down
97
What are the monomers of RNA?
nucleotides
98
What is the sugar in RNA called?
Ribose sugar
99
What four different nitrogenous bases are used in RNA
adenine
uracil
guanine
cytosine
100
In RNA, ___ replaces the nitrogenous base ___ found in DNA
uracil replaces thymine
101
Are there base pairs in RNA?
No as RNA is single stranded
102
What three types of RNA are there?
Messenger RNA
Ribosomal RNA
Transfer RNA
103
Where is mRNA formed?
in the nucleus
104
Where does mRNA move to from the nucleus?
moves out of the nucleus to attach to the ribosome in the cytoplasm
105
What is the function of mRNA?
It copies the genetic code for a specific protein from the DNA and carries it to the ribosome in the cytoplasm
106
What is the function of rRNA (Ribosomal RNA)?
It combines with other molecules to form the ribosomes in the cytoplasm which are the site of protein synthesis
107
Where is tRNA found?
In the cytoplasm
108
What is the function of tRNA?
- It carries amino acids to the mRNA on the ribosome
| - arranges them in the correct order according to the code of the mRNA
109
DNA and RNA both contain ___ alternating with ___
sugar alternating with phosphate
110
What nitrogenous bases do DNA and RNA both contain?
adenine
guanine
cytosine
111
What do DNA and RNA both play a role in?
protein synthesis
112
What shape is RNA?
single stranded
113
Where is DNA found?
nucleus
chloroplast
mitrochondria
114
Where is RNA found?
nucleus
| cytoplasm
115
What types of RNA play an important role is protein synthesis?
All three types of RNA
| mRNA, tRNA, rRNA
116
When does protein synthesis occur?
When there is a need for a specific protein
117
What stages happens in protein synthesis?
transcription
| translation
118
Briefly, what happens during the transcription stage of protein synthesis?
the mRNA copies the genetic code of a specific protein from a section of the DNA molecule
119
Briefly, what happens during the translation stage of the protein synthesis process
the genetic code of the mRNA is translated into a protein
120
Where in the cell does transcription take place?
in the nucleus
121
What does transcribe mean?
copy
122
How are mRNA strands transcribed?
with the help of an enzyme
123
New mRNA sequences are ___ to their DNA template
complementary
124
Does the whole DNA unwind in the transcription process of protein synthesis?
No only a small section of DNA containing the protein unwinds to its ladder shape.
125
What happens when the DNA strands unzip in the transcription process of protein synthesis?
The weak hydrogen bonds between the nitrogen bases break
| This is controlled by an enzyme
126
In what part of the transcription processs of protein synthesis is an enzyme required?
When the two DNA strands unzip
127
Are both (unzipped) strands of DNA in the transcription process of protein synthesis used to form mRNA
No. one strand is used as a template to form mRNA.
128
Where are free RNA nucleotides in the cell found?
In the nucleoplasm
129
What happens to the free RNA nucleotides in the nucleoplasm in the transcription stage of the protein synthesis process?
The free RNA nucleotides in the nucleoplasm pair with the nucleotides on the exposed 'template' DNA strand to form the mRNA.
130
The mRNA is ___ to the DNA
complementary
131
What happens once the free RNA nucleotides in the nucleoplasm pair with the nucleotides on the DNA?
The mRNA strand separates from the DNA
132
What do three adjacent bases on the mRNA make up?
a codon
133
What codes for an amino acid?
a codon
134
What moves out of the nucleus through the nucleopores during the transcription phase of the protein synthesis process?
mRNA
135
What happens once the mRNA has moved out of the nucleopores during the transcription process of the protein synthesis process?
The two strands of DNA join and return to their double-stranded helical shape
136
Once the newly-formed mRNA has left the nucleus and moved into the cytoplasm, where does it go during the translation stage of the protein synthesis process?
It attaches itself to the surface of a ribosome
137
How is the mRNA positioned when the mRNA has attached itself to the surface of a ribosome during the translation stage of the protein synthesis process?
The nitrogen bases of the mRNA strand are exposed
138
What are three exposed bases on a tRNA collectively called?
an anticodon
139
The anticodons are ___ to the codons on the mRNA
complementary
140
What collects free-floating amino acids in the cytoplasm?
The tRNA molecules, as determined by their anticodons
141
Where do the tRNA molecules move during the translation stage of the protein synthesis process?
the tRNA molecules move to the ribosome where the mRNA strands are attached
142
What happens once the tRNA molecules move to the ribosome during the translation stage of the protein synthesis process?
The anticodon of the tRNA links with the codon on the mRNA
143
What allows the amino acids to be in a certain order to form a specific protein?
The tRNA molecules place the amino acids in a certain order when the anticodon of the tRNA links with the codon on the mRNA
144
Where does the ribosome move during the translation stage of the protein synthesis process?
Along the full length of the mRNA strand
145
What type of bonds are used to link amino acids together during the translation stage of the protein synthesis process?
peptide bonds
146
Where are enzymes required during the translation stage of the protein synthesis process?
When the amino acids link together by means of peptide bonds
147
What happens once the tRNA molecules have released their amino acids during the translation stage of the protein synthesis process?
the tRNA molecules move back into the cytoplasm where they can pick up more amino acids to carry to the ribosomes
148
How many amino acids is a protein composed of?
50 or more amino acids
149
How are the amino acids making up a protein arranged?
in the order that corresponds to the order of codons on the mRNA strand
150
Does DNA usually replicate accurately?
Yes, but sometimes, there are copying errors
151
What results from a copying error in DNA replication?
The wrong nucleotide or too many nucleotides being inserted into a sequence
152
How can most replication mistakes in DNA be repaired?
by DNA repair processes that are brought about by repair enzymes
153
What happens if some replication errors are not detected and corrected?
They can become permanent mutations.
154
What can mutations lead to?
genetic problems
| cancer
155
If occasional copying errors are useful, what does this enable the species to do?
this enables a species to adapt, which helps the organisms survive
156
What can increase genetic variation within a species
mutations
