Unit 1: DNA and the genome Flashcards
(417 cards)
1
Q
what does the nucleus store?
A
genetic information
2
Q
where are chromosomes found?
A
nucleus
3
Q
what packages the genetic information?
A
chromosomes
4
Q
what are chromosomes made of?
A
DNA
5
Q
what is the shape of DNA?
A
two strands which form a twisted structure (double helix)
6
Q
what is each strand of DNA made up of?
A
nucleotides
7
Q
what are the three parts of a nucleotide?
A
phosphate, deoxyribose sugar, base
8
Q
what are nucleotides in a chain joined together by?
A
sugar-phosphate bonds
9
Q
what is the name for a chain of nucleotides?
A
polynucleotides
10
Q
what type of backbone does dna have?
A
sugar-phosphate backbone
11
Q
where do the nucleotides bond at?
A
3’ and 5’
12
Q
how is 3’ pronounced?
A
three prime
13
Q
what base pairs with thymine?
A
adenine
14
Q
what base pairs with guanine?
A
cytostine
15
Q
what base pairs with adenine?
A
thymine
16
Q
what base pairs with cytosine?
A
guanine
17
Q
what joins the base pairs?
A
hydrogen bonds
18
Q
what is the shape of the double helix called?
A
anti-parallel
19
Q
what does anti-parallel mean in dna?
A
the nucleotides on one side goes from 5’ to 3’ and the other 3’ to 5’
21
Q
describe a prokaryotic cell
A
- dna is not housed within nuclear envelope
- dna is stored in single circular chromosome
- small circular SNA is called plasmid
21
Q
give an example of a prokaryotic cell
A
bacteria cell
22
Q
describe how dna is stored in prokaryotic cells?
A
dna is not housed within nuclear envelope, it is stored in a single circular chromosome
23
Q
where is dna not stored in a prokaryotic cell?
A
the nucleus
24
Q
where is dna stored in a prokaryotic cell?
A
in small circular dna (called plasmids)
25
what is a plasmid
small circular dna
26
what is the purpose of dna supercoiling?
to package dna to fit inside a cell
27
describe the relationship of dna in and histones in eukaryotes
each nucleosome consists of clusters of 8 histone proteins , the dna is weapped around it
28
describe the storage of dna in eukaryotic cells
dna is housed within a nuclear envelope, linear dna is packaged with proteins
29
where are circular chromosomes also found?
mitochondria and chloroplasts
30
What is the DNA parental strand composed of?
2 complementary strands
31
What is step 1 of dna replication?
Hydrogen bonds between the bases break - separating the strands
32
What is step 2 of dna replication?
Free nucleotides start to line up with complementary nucleotides
33
What is step 3 of dna replication?
The sugar phosphate bonds form. Two dna molecules identical to the parental molecule have been formed
34
What are the 3 steps of dna replication?
1. Hydrogen bonds between the bases break - separating the strands
2. Free nucleotides start to line up with complementary nucleotides
3. The sugar phosphate bonds form. Two dna molecules identical to the parental molecule have been formed
35
What does the enzyme DNA polymerase control?
Controls the formation of the sugar-phosphate bonds when making the new strand
36
What enzyme controls the formation of the sugar phosphate bonds when making the new strand?
DNA polymerase
37
What does dna polymerase do?
Adds dna nucleotides using complementary base pairings to the 3’ end of the new dna strand
38
What does dna polymerase need to start replication?
Primers
39
What is a primer?
A short strand of nucleotides which binds the 3’ end of the template DNA strand allowing polymerase to add DNA nucleotides
40
What is PCR?
DNA replication in a lab setting
41
What is the full name of PCR?
polymerase chain reaction
42
Another name for dna replication
DNA amplification
43
Why is dna replication sometimes called dna amplification?
Because PCR allows specific sections of dna to be amplified in vitro
44
What is the meaning of in vitro?
In glass
45
First stage of PCR?
1. DNA is heated at 92-98 degrees Celsius for a few seconds. This causes the dna to separate
46
What temperature is dna heated to in stage 1 of PCR?
92-98 C
47
What stage of PCR heats dna to 92-98 C?
Stage 1
48
What is stage 2 of PCR?
2. Dna is cooled to 50 - 65 C. This allows short primers to bind to target sequence
49
What temperature is dna heated to in stage 2 of PCR?
50 - 65 C
50
What stage of PCR heats dna to 50 - 65 C?
Stage 2
51
What is stage 3 of PCR?
DNA is heated to 70 - 80 C. This allows a heat tolerant DNA polymerase to replicate the dna.
52
What temperature is dna heated to in stage 3 of PCR?
70 - 80 C
53
What stage of PCR heats dna to 70 - 80 C?
Stage 3
54
What is the number of double stranded copies of dna after 0 PCR cycles?
1
55
What is the number of double stranded copies of original DNA after 1 cycle?
2
56
What is the number of double stranded copies of original DNA after 1 cycle?
2
57
What is the number of double stranded copies of orignal DNA after 0 PCR cycles?
1
58
What is the number of double stranded copies of orignal DNA after 1 PCR cycles?
2
59
What is the number of double stranded copies of orignal DNA after 2 PCR cycles?
4
60
Three requirements for PCR
1. Primers
2. Supply of nucleotides
3. Heat tolerant DNA polymerase
61
Description of an example of PCR
Genetic Disorder Diagnosis - DNA sequences that are known to indicate certain genetic disorders or diseases are amplified using PCR for diagnosis.
62
Why does DNA supercoil
So that dna fits inside a cell
63
DNA in eukaryotes
- chromosomes tightly coiled and packaged within histones
64
What cells have chromosomes tightly coiled and packaged within histones
Eukaryotes
65
Properties of a eukaryotic cell
- dna is housed within a nuclear envelope
- linear DNA is packaged with proteins
- circular chromosomes are also found in mitochondria and chloroplasts
66
Why is yeast a special example of a eukaryotes
It also has plasmids
67
Special example of a eukaryote
Yeast
68
DNA replication on the leading strand
1. dna is unwound and hydrogen bonds between bases break to form two template strands
2. a DNA primer binds to the 3' end of the template DNA being copied
3. DNA polymerase can add free nucleotides in one direction
this is a CONTINUOUS PROCESS until the LEADING STRAND is copied
69
DNA polymerase can only be added to ___ the end of the new strand
3'
70
Describe how DNA rectification takes place on the 5' to 3' strand (lagging strand)
- many primers attach along the strand
- these are extended by the DNA polymerase
- these fragments are then joined by the enzyme ligase
this is a discontinuous process
71
requirements for DNA replication
- DNA (to act as template)
- primers
- a supply of the 4 types of nucleotide
- DNA polymerase
- ligase enzymes
- a supply of ATP (energy)
72
function of ligase
enzyme which joins fragments together
73
function of unwinding and breaking bonds between bases
template DNA strand does this in preparation for replication
74
function of primer
starting point for DNA synthesis
75
function of semi-conservative strands wind up
2 genetically identical strands are synthesised
76
function of DNA polymerase
enzyme that adds nucleotides to new strand
77
How is dna packaged in prokaryotes
Circular chromosomes
Always have plasmids
78
Circular chromosomes
Always have plasmids
How dna is packaged in prokaryotes
79
How is dna packaged in eukaryotes
Linear chromosomes with histones
Always have plasmids
80
Full names of all bases
Cytosine
Guanine
Thymine
Adenine
81
Linear chromosomes with histones
Always have plasmids
How is dna packaged in eukaryotes
82
Gene expression
The transcription and translation of DNA sequences
83
The transcription and translation of DNA sequences
Gene expression
84
What is
DNA —-> RNA
transcription
85
transcription
DNA —-> RNA
86
What is
RNA —> AMINO ACID CHAIN
translation
87
Translation
RNA —> AMINO ACID CHAIN
88
mRNA
Carries a copy of DNA code from nucleus to the ribosome
89
Carries a copy of DNA code from nucleus to the ribosome
mRNA
90
what does mRNA carry from the nucleus to the ribosome
a copy of the DNA code
91
where does mRNA carry a copy of the DNA code to and from?
From the nucleus to the ribosome
92
tRNA
folds due to complementary base pairings
Each tRNA carries it’s specific amino acid to the ribosome
93
folds due to complementary base pairings
Each tRNA carriers it’s specific amino acid to the ribosome
tRNA
94
folding
AMINO ACID —> PROTEIN
95
What is …
AMINO ACID —> PROTEIN
Folding
96
Why does tRNA fold
Complementary base pairings
97
what does complementary base pairings cause tRNA to do
fold
98
what does each tRNA carry
It’s specific amino acid
99
where does tRNA carry it’s specific amino acid to
The ribosome
100
rRNA
proteins form in the ribosome with rRNA
101
What is phenotype determined by
Proteins produced as a result of Gene expression
102
what does Proteins produced as a result of gene expression determine
Phenotype
103
What does gene expression involve
1. Transcription of DNA sequences
2. Translation of DNA sequences
104
what involves
1. Transcription of DNA sequences
2. Translation of DNA sequences
Gene expression
105
only a _____ of the genes in a cell are expressed
Fraction
106
only a fraction of the genes in a cell are ________
Expressed
107
What do amino acids build up to
Protein molecule
108
What do three bases carry the code for
One amino acid
109
What carries the code for one amino acid
Three bases
110
What makes each amino acid different
The combination and sequence of bases
111
DNA nucleotide
Phosphate deoxyribose sugar base
112
Phosphate deoxyribose sugar base
DNA nucleotides
113
RNA nucleotide
Phosphate ribose sugar base
114
Phosphate ribose sugar base
RNA nulceotide
115
Similarities of DNA and RNA nucleotides
1. Phosphate
2. Base
116
1. Phosphate
2. Base
Similarities of DNA and RNA nucleotides
117
difference of DNA and RNA nucleotides
DNA has deoxyribose sugar
RNA has ribose sugar
DNA has Thymine
RNA has uracil
118
DNA has deoxyribose sugar
RNA has ribose sugar
DNA has Thymine
RNA has uracil
Difference of DNA and RNA nucleotides
119
in RNA, what replaces thymine?
Uracil
120
What does uracil pair with
Adenine
121
DNA overview
Double stranded
Has thymine
No uracil
122
Double stranded
Has thymine
No uracil
DNA overview
123
RNA overview
Single stranded
No thymine
Has uracil
124
Single stranded
No thymine
Has uracil
RNA overview
125
Gene
A section of DNA which carries the code for the production of a protein
126
A section of DNA which carries the code for the production of a protein
Gene
127
Protein synthesis
When the instructions on DNA sequences are carried to ribosomes where they are translated into proteins
128
When the instructions on DNA sequences are carried to ribosomes where they are translated into proteins
Protein synthesis
129
where is mRNA transcribed
the nucleus
130
what is transcribed in the nucleus
mRNA
131
Codon
Three DNA bases on mRNA
132
Three bases on mRNA
Codon
133
What is mRNA transcribed from
DNA sequences
134
What is mRNA translated into
Proteins
135
Where does mRNA get translated
The cytoplasm
136
what is translated in the cytoplasm
the mRNA
137
what translates mRNA
ribosomes
138
where is the mRNA molecule produced
Nucleus
139
How does mRNA leave the nucleus
Through a pore in the nuclear membrane
140
what leaves the nucleus Through a pore in the nuclear membrane
mRNA
141
where does mRNA go after leaving the nucleus
Cytoplasm
142
RNA polymerase
enzyme responsible for the transcription of DNA
143
enzyme responsible for the transcription of DNA
RNA polymerase
144
What does RNA polymerase do
1. Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
2. RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
145
1. Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
2. RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
What does RNA polymerase do
146
First thing RNA polymerase does
1. Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
147
Second thing RNA polymerase does
2. RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
148
2. RNA polymerase then adds nucleotides using complementary base pairings (U instead of T)
Second thing RNA polymerase does
149
1. Moves along the DNA strand unwinding the double helix and breaking the hydrogen bonds between the bases
First thing DNA polymerase does
150
What does RNA polymerase produce
mRNA transcript
151
RNA polymerase adds nucleotides onto the ____ end of the _____ _____ _____
3’
Growing mRNA molecule
152
What means that the mRNA produced will be complementary to the DNA
base pairing rules
153
what is mRNA because of base pairings rules
Complementary to DNA
154
intron
Non coding region of a gene
155
Non coding region of a gene
Intron
156
Exon
Coding region of a gene
157
Coding region of a gene
Exon
158
Exons are ______
Expressed
159
Transcription
DNA > PRIMARY TRANSCRIPT
160
DNA > PRIMARY TRANSCRIPT
transcription
161
What are introns removed from
The primary transcript
162
What are removed from the primary transcript
Introns
163
In the formation of the mature transcript, exons are …
Sliced together
164
What is spliced together in the formation of the mature transcript
Exons
165
What is produced when exons are spliced together
Mature transcript
166
Where is the mature transcript produced
Nucleus
167
Where does the mature transcript go after production
Cytoplasm
168
After mRNA has been transcribed, what is removed
Introns
169
When are introns removed
After mRNA has been transcribed
170
The order of exons is _______ during slicing
Unchanged
171
Where is transfer RNA found
The cytoplasm
172
Why do tRNA fold
Complementary base pairings
173
what does tRNA have
1. Anti codon site
2. Amino acid site
174
1. Anti codon site
2. Amino acid site
tRNA
175
What does each tRNA molecule carry
It’s specific amino acid
176
Where does each tRNA carry its amino acid to and from
From the cytoplasm to the ribosome
177
where are anti codon found
tRNA
178
ribosomes
small almost spherical structures found in all cells
179
small almost spherical structures found in all cells
ribosomes
180
what form the ribosome
rRNA and proteins
181
what do rRNA and proteins form
ribosome
182
where are ribosomes found
some are free in the cytoplasm
others attached to the endoplasmic reticulum
183
what are found in.....
some are free in the cytoplasm
others attached to the endoplasmic reticulum
ribosomes
184
what are ribosome the site of
translation of mRNA into protein
185
where does translation of mRNA into protein happen
ribosomes in the cytoplasm
186
where does translation begin
at the start codon
187
what begins at the start codon
translation
188
what ends at the stop codon
translation
189
where does translation end
the stop codon
190
what do anti codons bond to
codons
191
how do anticodons bond to codons
buy complementary base pairings
192
what happen when anticodons bond to codons
translates the genetic code into a sequence of amino acids
193
translates the genetic code into a sequence of amino acids
what happens when anticodons bond to codons
194
what does the anticodons bonding to the codons form
peptide bonds
195
when do peptide bonds form
when anticodons bond to codons
196
what joins amino acids together
peptide bonds
197
what do peptide bond join together
amino acids
198
what does tRNA do when peptide bonds form
tRNA leaves the ribosome
199
when does protein synthesis end
at the stop codon
200
_________ proteins can be expressed from one gene, because of ___________
different
alternative splicing
201
different proteins can be __________ from __________, because of alternative splicing
expressed from one gene
202
different ___________ are produced from the same ____________ depending on which ________________
different mature mRNA transcripts are produced from the same primary strand depending on which exon are retained
203
cellular differentiation
the process by which a cell expresses certain genes to produce proteins characteristic for that type of cell
204
the process by which a cell expresses certain genes to produce proteins characteristic for that type of cell
cellular differentiation
205
what does cellular differentiation allow a cell do to
to carry out specialised functions
206
what allows cells to carry out specialised functions
cellular differentiation
207
what does every cell in a body have?
all genes
208
what cells have all genes
every cell
209
what can a cell do to its genes
switch them on or off when they are required
210
why do cells turn genes on and off
to not waste energy
211
example of selective gene expression
insulin produced in pancreas cells, not in heart or brain cells
212
insulin produced in pancreas cells, not in heart or brain cells
example of selective gene expression
213
in multicellular plants, where is growth restricted to
regions called meristems
214
in what is growth restricted to meristems
multicellular plants
215
meristems
regions of unspecialised cells in plants that can divide and/or differentiate
216
regions of unspecialised cells in plants that can divide and/or differentiate
meristems
217
each cell type has a ...
different and specific
1. structure
2. shape
3. size
4. function
218
different and specific
1. structure
2. shape
3. size
4. function
each cell has a
219
stem cells
unspecialised cells in an animal that can....
1. divide and self renew through cell division
2. differentiate into specialised cells
220
unspecialised cells in an animal that can....
1. divide and self renew through cell division
2. differentiate into specialised cells
stem cells
221
sources of stem cells
1. embryonic
2. tissue
222
1. embryonic
2. tissue
sources of stem cells
223
embryonic stem cells extraction
zygote > blastocyst > stem cells
224
zygote > blastocyst > stem cells
embryonic stem cells
225
tissue stem cells extraction
bone marrow > bone marrow w lots of dif cells > bone marrow w stem cells > muscle cells, neural cells, etc
226
bone marrow > bone marrow w lots of dif cells > bone marrow w stem cells > muscle cells, neural cells, etc
tissue stem cells extraction
227
embryonic stems cells can _________ into ____ cell types in an organism
differentiate, all
228
pluripotent
cell can differentiate into all cell types in an organism
229
cell can differentiate into all cell types in an organism
pluripotent
230
what can embryonic cells do with genes
switch them all on and off
231
when do embryonic cells occur
in 5 - 7 day old embryos
232
what stem cells can switch all genes on and off
embryonic cells
233
tissue stem cells can differentiate into _______________ in a ________
all types of cell found in a particular tissue type
234
tissue stem cells can differentiate into all types of cell found in a particular tissue type
multipotent
235
multipotent
tissue stem cells can differentiate into all types of cell found in a particular tissue type
236
what are tissue stem cells involved in
the growth, repair, and renewal of the cells found in that tissue
237
what stem cells are involved in the growth, repair, and renewal of the cells found in that tissue
tissue stem cells
238
where are tissue stem cells found
bone marrow, muscle, and brain tissue in the body
239
what stem cells are found in bone marrow, muscle, and brain tissue in the body
tissue stem cells
240
corneal repair
1. corneal limbus stem cells grown in a lab
2. corneal stem cells trasplanted onto diseased cornea
241
1. corneal limbus stem cells grown in a lab
2. corneal stem cells trasplanted onto diseased cornea
corneal repair
242
first step corneal repair
1. corneal limbus stem cells grown in a lab
243
1. corneal limbus stem cells grown in a lab
first step corneal repair
244
second step corneal repair
2. corneal stem cells trasplanted onto diseased cornea
245
2. corneal stem cells trasplanted onto diseased cornea
second step corneal repair
246
what does stem cell research provide info on
how cell processes such as cell growth, differentiation, and gene regulation occur
247
how cell processes such as cell growth, differentiation, and gene regulation occur
what does stem cell research provide info on
248
what can stem cells be used for
used as model cells to study how diseases develop for drug testing
249
used as model cells to study how diseases develop for drug testing
what stem cells can be used for
250
why are there ethical issues in stem cells
the destruction of embryos
251
the destruction of embryos
ethical issues in stem cells
252
Genome
The entire hereditary information encoded in the DNA of an organism
253
The entire hereditary information encoded in the DNA of an organism
Genome
254
Humans have _________ base pairs of DNA
Humans have 3 billion base pairs of DNA
255
Humans have 3 billion ______________
Humans have 3 billion base pairs of DNA
256
What do base pairs contain
1. Protein coding genes
2. Non protein coding genes
257
1. Protein coding genes
2. Non protein coding genes
Base pairs of DNA
258
Most of the eukaryotic genome consists of ____________
Most of the eukaryotic genome consists of non coding genes
259
What % do coding regions make up of DNA
2%
260
many non protein coding regions are _____________
many non protein coding regions are made of DNA sequences which are repeated over and over
261
________________ DNA sequences which are repeated over and over
many non protein coding regions are made of DNA sequences which are repeated over and over
262
What do non coding sequences do
1. Regulate transcriptions
2. Transcribed into RNA but never translated, like tRNA
263
What...
1. Regulate transcriptions
2. Transcribed into RNA but never translated, like tRNA
Non-protein-coding regions
264
Mutations
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised
265
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised
Mutations
266
Mutations arise ______ and at _______
Mutations arise spontaneously and at random
267
What do mutation rates differ between
Different genes and different organisms
268
Types of mutations
1. Single gene mutations
2. Chromosome structure mutations
269
1. Single gene mutations
2. Chromosome structure mutations
Types of mutations
270
Single gene mutations
A change in one of the base pairs in the DNA sequence of a single gene
271
A change in one of the base pairs in the DNA sequence of a single gene
Single gene mutations
272
What do single gene mutations occur in
The protein coding sequence or the regulatory sequences which control expression of the gene
273
What occur in the protein coding sequence or the regulatory sequences which control expression of the gene
Single gene mutations
274
Three single gene mutations
1. Deletion
2. Insertion
3. Substitution
275
1. Deletion
2. Insertion
3. Substitution
3 types of single gene mutations
276
Deletion
One nucleotide is deleted from the nucleotide sequence
277
When one nucleotide is deleted from the nucleotide sequence
Deletion
278
One nucleotide is inserted into the nucleotide sequence
Insertion
279
Insertion
One nucleotide is inserted into the nucleotide sequence
280
One nucleotide is swapped for another nucleotide in the sequence
Substitution
281
Impact of single gene mutations
Missense mutations
Nonsense mutations
Splice site mutations
Frameshift mutations
282
Missense mutations
Nonsense mutations
Splice site mutations
Frameshift mutations
Impact of single gene mutations
283
Missense
One amino acid is changed for another
May result in a non functional protein or have little effect on protein
284
One amino acid is changed for another
May result in a non functional protein or have little effect on protein
Missense
285
Nonsense
Premature step codon produced
Shorter protein synthesised
286
Premature step codon produced
Shorter protein synthesised
Nonsense
287
Splice site mutation
Some introns being retained and/or some exons not being included in mature transcript
Protein doesn't function properly
288
Some introns being retained and/or some exons not being included in mature transcript
Protein doesn't function properly
Splice site mutations
289
Thalassemia
Disease caused by a defect inhoemeglobin synthesis, caused by a splice site mutation
290
Disease caused by a defect inhoemeglobin synthesis, caused by a splice site mutation
Thalassemia
291
Example of splice site mutation
Thalassemia
292
Mutations from substitutions
Missense
Nonsense
Splice site
293
A mutation in what can result in....
Missense
Nonsense
Splice site
Substitution
294
Frame shift mutations
Cause all of the codons and amino acids after the mutationto be changed
Has a major effect on the structure of the protein produced
295
all of the codons and amino acids after the mutationto be changed
Has a major effect on the structure of the protein produced
Frame-shift-mentations
296
What causes frame-shift mutations
Insertion or deletion
297
What does insertion cause
Frame shift mutations
298
What does deletion cause
Frame shift mutations
299
Chromosome structure mutations
A change in the chromosome structure due to the breakage of one a more chromosomes
300
A change in the chromosome structure due to the breakage of one a more chromosomes
Chromosome structure mutations
301
The substantial change in chromosome mutation results in what
Lethal
302
What can be the result of insertion
Frame shift mutations
303
What can be the result of substitution of a gene
Missense mutations
Nonsense mutations
Splice site mutations
304
What can be the result of deletion
Frame shift mutations
305
Types of chromosome structure mutations
Deletion
Duplication
Inversion
Translocation
306
Deletion
Duplication
Inversion
Translocation
Types of chromosome mutations
307
Chromosome deletion
A section of a chromosome is removed
308
A section of a chromosome is removed
Chromosome deletion
309
Effect of chromosome deletion
Drastic effect as genes are lost
310
Example of chromosome deletion
Deletion of a party of chromosome 5 leads to Cri du Chat
311
Duplication
A section of a chromosome is added from its homologous partner
312
A section of a chromosome is added from its homologous partner
Duplication
313
Effects of duplication
Set of genes are repeated
Can be detrimental but also important in evolution
314
Set of genes are repeated
Can be detrimental but also important in evolution
Duplication
315
Example of duplication
Duplication of oncogenes is a common cause of cancer
316
Evolutionary importance of gene duplication
Allows potential beneficial mutations to occur In a duplicated gene whilst original gene can still be expressed to produce its protein
317
Inversion
A section of chromosome is reversed
318
A section of chromosome is reversed
Inversion
319
Example of inversion
One cause of haemophilia A is the inversion within a blood clotting gene
320
Translocation
A section of one chromosome is added to another chromosome, not its homologous partner
321
A section of one chromosome is added to another chromosome, not its homologous partner
Translocation
322
Example of translocation
One type of Down’s syndrome is caused by this
323
Evolution
The changes in organisms over generations as a result of genetic variation
324
The changes in organisms over generations as a result of genetic variation
Evolution
325
Natural selection
The non random increase in the frequency of DNA sequences that increase survival and the non random decrease in the frequency of deleterious sequences
326
The non random increase in the frequency of DNA sequences that increase survival and the non random decrease in the frequency of deleterious sequences
Natural selection
327
Deleterious sequence
Any sequence that may produce a protein that causes harm
328
Any sequence that may produce a protein that causes harm
Deleterious sequence
329
Gene pool
The total of all the different genes in a population
330
The total of all the different genes in a population
Gene pool
331
What happens if a species is under no selective pressure
Frequencies of individual alleles will stay the same from generation to generation
332
Types of selection
Stabilising
Directional
Disruptive
333
Selection pressure
An environmental change that affects an organisms ability to survive and reproduce
334
An environmental change that affects an organisms ability to survive and reproduce
Selection pressure
335
Example of selection pressure
Increased competition
Temperature change
New diseases
336
Stabilising selection
An average phenotype is selected for and extremes of the phenotype are selected against
337
An average phenotype is selected for and extremes of the phenotype are selected against
Stabilising selection
338
What does stabilising selection cause
Reducing in genetic diversity
339
Directional selection
One extreme of the phenotype range is selected for
340
One extreme of the phenotype range is selected for
Directional selection
341
When is directional selection common
During periods of environmental change
342
What selection happens during periods of environmental change
Directional selection
343
Disruptive selection
Two or more phenotypes are selected for
344
Two or more phenotypes are selected for
Disruptive selection
345
What can disruptive selection result in
The population being split into two
346
What does vertical transfer happen by
Asexual and sexual reproduction
347
Natural selection happens much more _________ in prokaryotes
Quickly
348
Why can prokaryotes go through natural selection much faster
Prokaryotes can exchange genetic material horizontally
349
Vertical transfer
The transfer of genetic sequences from parents to offspring
350
The transfer of genetic sequences from parents to offspring
Vertical transfer
351
Horizontal transfer
When genes are transfer between individuals in the same generation
352
When genes are transfer between individuals in the same generation
Horizontal transfer
353
Species
a group of organisms capable of interbreeding and producing fertile offspring
354
a group of organisms capable of interbreeding and producing fertile offspring
Species
355
a group of organisms capable of interbreeding and producing fertile offspring
Species
356
Speciation
The generation of new biological species by evolution
357
The generation of new biological species by evolution
Speciation
358
Types of speciation
Allopathic
Sympatric
359
Geographical barriers cause……
Allopatric speciation
360
Behavioural barriers cause……….
Sympatric speciation
361
Ecological barriers cause…….
Sympatric speciation
362
Allopatric speciation
When gene flow between 2 or more populations is prevented by a geographical barrier
363
When gene flow between 2 or more populations is prevented by a geographical barrier
Allopatric speciation
364
Allopatric speciation example
Rivers
Sea
Mountain ranges
365
Steps of speciation
1. Isolation
2. Mutation
3. Natural selection
4. Speciation
366
Sympatric speciation
Two or more populations live in close proximity in the same environment, but still become genetically isolated
367
Two or more populations live in close proximity in the same environment, but still become genetically isolated
Sympatric speciation
368
What causes Sympatric speciation
Behavioural or ecological barriers
369
What causes allopatric speciation
Geographical barrier
370
Ecological barrier
Groups not genetically isolated from each other
Isolated by other things such as occupying different habitats or breeding areas
371
Groups not genetically isolated from each other
Isolated by other things such as occupying different habitats or breeding areas
Ecological barrier
372
Behavioural barrier
Breeding between groups working a population may not be possible because of differences in courtship behaviour
373
Breeding between groups working a population may not be possible because of differences in courtship behaviour
Behavioural barrier
374
Stage 1 of speciation
Large interbreeding population sharing the same ecological niche
375
Large interbreeding population sharing the same ecological niche
Stage 1 of speciation
376
Stage 2 of speciation
Alternative ecological niches appears
Some members of the population start to exploit this niche
377
Alternative ecological niches appears
Some members of the population start to exploit this niche
Stage 2 of speciation
378
Stage 3 of speciation
The two populations now exploit different resources and no longer interbreed
Behavioural had become an isolating barrier
379
The two populations now exploit different resources and no longer interbreed
Behavioural had become an isolating barrier
Stage 3 of speciation
380
Stage 4 of speciation
Mutants better adapted to exploit the new resources and successfully breed
Both groups have had mutations
381
Mutants better adapted to exploit the new resources and successfully breed
Both groups have had mutations
Stage 4 of speciation
382
Stage 5 of speciation
Natural selection factors the new mutants
and eventually over a period of time two genetically distinct species are formed which can no longer interbreeding
383
Mutants better adapted to exploit the new resources and successfully breed
Both groups have had mutations
Stage 5 of speciation
384
genomics
the study of genes
385
the study of genes
genomics
386
What must you first do to study genomics
Determine the entire DNA sequence of the organism
387
When was the entire human genome sequenced
2003
388
Reasons for genomic sequencing
accurate diagnoses
specific pest control
Model sequencing
389
Genomic sequencing accurate diagnoses
Disease causing organisms have been sequenced
Eg. Viruses to help with accurate diagnoses
390
Genomic sequencing, specific pest control
Pest sequences have been sequenced to develop more specific measures to control rather than using general pesticides
391
Genomic sequencing, model sequencing
Model organisms have been sequenced so that they can be used in medical research in place of mammals,
reducing ethical concerns and costs
392
Bioinformatics
The use of computers and statistical analysis to identify and compare sequence date
393
The use of computers and statistical analysis to identify and compare sequence date
Bioinformatics
394
What can computer programs be used for in bioinformatics
To identify base sequences by looking for sequences similar to known genes
395
What can highly conserved dna sequences by used for
To compare the genomes of two species
396
What can be used to compare the genome of two species
Highly conserved DNA sequences
396
Highly conserved sequences means..
Species more closely related
397
Phylogenetics
The study of evolutionary history and relationships
398
The study of evolutionary history and relationships
Phylogenetics
399
What do phylogenetic trees show
How organisms are thought to have evolved into different species over time
400
What shows how organisms are thought to have evolved into different species over time
Phylogenetic trees
401
The further apart the species are on a phylogenetic tree………
The more distantly related they are
402
Over time, a group of closely related relative living things will accumulate __________ that will gradually __________
Mutations
Alter the genome
403
What do molecular clocks show
When species diverged during evolution
404
What do molecular clocks assume
A constant mutation rate
405
Requirements for molecular clocks
Genome sequence dna
Fossil evidence
406
Pharmocogenetics
The use of genome information in the choice of drugs
407
The use of genome information in the choice of drugs
Pharmocogenetics
408
What could knowing the genome sequence of a person be used for
Select the most effective drugs
And dosages
409
410
DNA in prokaryotes
Circular chromosomes and plasmids
411
Where is dna found in prokaryotes
Cytoplasm
412
Eukaryotes dna
Linear chromosomes packaged with histones
Circular chromosomes found in mitochondria
413
Where is linear dna found in eukaryotes
Nucleus
414
Exception in eukaryotes
Yeast has plasmids
415
Transcription summary
RNA polymerase unwinds DNA
hydrogen bonds between bases break
RNA polymerase attaches rna nucleotides with their complementary nucleotides
A primary transcript is produced
Exons - coding regions
Introns - non coding regions
Exons are spliced together to form mature transcript
416
Translation
tRNA has an amino acid attachment site and an anti codon attachment site
tRNA carries its specific amino acid
Anticodons are complementary with codons on mRNA
There are start and stop codons on mRNA
peptide bonds firm between amino acids
