Genetics Chapter 3

  • Created by: Lotto65
  • Created on: 31-03-18 19:59
In prokaryotes, what shape is the DNA molecule in the one chromosome?
1 of 219
What are the shapes of the DNA molecules in eukaryotes?
2 of 219
Do eukaryotes have plasmids?
3 of 219
What is the difference between eukaryote and prokaryote DNA in terms of proteins associated with it?
Eukaryotes have DNA associated with histone proteins while prokaryotes have naked DNA not associated with any proteins
4 of 219
How many chromosome do eukaryotes have?
Two or more DIFFERENT chromosomes
5 of 219
Overall, what are the differences between eukaryote and prokaryote DNA/ chromosomes?
Eukaryotes: 2 or more different chromosomes, no plasmids, histone proteins, linear DNA; Prokaryotes: Plasmids, One chromosome, naked DNA, circular DNA molecule
6 of 219
At what stage of mitosis are chromosomes at their minimum length in eukaryotes?
7 of 219
What is identical in sister chromatids?
Their DNA base sequences
8 of 219
Why are the base sequences identical in sister chromatids?
Produced by replication during interphase
9 of 219
What holds sister chromatids together?
10 of 219
How does autoradiography work?
Thin sections of cells are coated with photographic film and left in darkness for days or weeks. The film is then developed and viewed under an electron microscope
11 of 219
What does autoradiography show?
The structure of cells and where radioactively labelled substances are located
12 of 219
What does each black dot show on an electron microscope?
Where a radioactive atom decayed and gave out radiation
13 of 219
What did John Cairns do?
Researched chromosomes of E.Coli. He grew E.Coli in a medium containing radioactive thymine to label the DNA but not RNA. Placed cells on a membrane, digested cell walls so DNA spilled. Covered DNA in photographic film and left in dark for 2 month
14 of 219
What did John Cairns discover?
DNA in E.Coli is circular and 1100 micrometres long. Discovered the length and shape of DNA in prokaryotes as well as that DNA replication is semi-conservative and starts at the origin and moves in opposite directions with two replication forks
15 of 219
What did other researchers find who researched eukaryotic chromosomes using John Cairn's method?
Eukaryotic DNA is linear and much longer than prokaryotic DNA. Eukaryotic chromosomes contain one very long DNA molecule not many shorter molecules.
16 of 219
What is the size of a genome?
The total amount of DNA in one set of chromosomes in that species
17 of 219
What is genome size measured in?
Millions of base pairs (bp)
18 of 219
What pH are histone proteins?
19 of 219
What is chromatin?
A complex of DNA found in interphase and only seen with an electron microscope
20 of 219
How can an organism have a large genome but a small number of genes?
It could have few protein-coding genes and lots of non-coding DNA
21 of 219
Arrange the homo sapiens, T2 phage, Paris Japonica woodland plant, E.Coli gut bacteria and drosophila melanogaster fruit fly in order of increasing genome size
T2 phage, E.Coli, Drosophila melanogaster, homo sapiens, Paris Japonica
22 of 219
What did John Cairns change to make radioactively labelled thymine?
Isotope of hydrogen with three as its mass number
23 of 219
What are homologous chromosomes?
Chromosomes of the same type (one from father, one from mother)
24 of 219
What is the same and different in homologous chromosomes?
Same genes in the same sequence but might have different alleles
25 of 219
What does diploid nucleus mean?
Pairs of homologous chromosomes
26 of 219
What does haploid nucleus mean?
One type of chromosome
27 of 219
What is the diploid cell called when haploid male and female gametes fuse?
28 of 219
What is a characteristic feature of species?
Chromosome number
29 of 219
Which pair of chromosomes is the sex chromosomes?
23rd pair
30 of 219
Which chromosome is bigger, the X or the Y chromosome?
31 of 219
What is a karyotype?
The number and type of chromosomes present in a cell or organism
32 of 219
What is a karyogram?
A photograph or diagram showing the homologous pairs of chromosomes of an organism in decreasing length
33 of 219
Why are karyograms made?
To study the karyotype of an individual
34 of 219
What are the functions of making karyograms of humans?
Determine the sex of the individual; Look for any chromosomal abnormalities if there are more or less than two chromosomes of each type
35 of 219
What is Klinefelter syndrome?
A male having 2X chromosomes and one Y chromosome
36 of 219
What is it called if someone has three chromosomes of a certain type?
37 of 219
Why must the chromosome number be halved in meiosis?
Otherwise with each generation, there would be double the number of chromosomes
38 of 219
What is meiosis?
A process that halves the chromosome number and allows a sexual life cycle with fusion of gametes
39 of 219
What does the letter 'n' represent?
Haploid number of chromosomes
40 of 219
What does '2n' mean?
Diploid number of chromosomes
41 of 219
How many haploid nuclei are produced from meiosis of one diploid cell?
42 of 219
How many chromatids in each chromosome are present after the first division of meiosis?
43 of 219
How many chromatids in each chromosome are present after the second division of meiosis?
44 of 219
What was present in a diploid cell before replication?
Two chromatids of each chromosome type
45 of 219
What happens to chromatids when replication occurs?
Each chromosome is formed from two sister chromatids to create a pair of homologous chromosomes
46 of 219
What halves the chromosome number in meiosis?
Separation of pairs of homologous chromosomes in the first stage of meiosis
47 of 219
What happens in prophase 1?
Supercoiling and condensation makes the chromosomes visible. Homologous chromosomes pair up (synapsis). Centrioles migrate to opposite poles and spindle fibres form. Nucleolus and nuclear membrane disintegrate. Crossing over to form chiasmata
48 of 219
What happens in metaphase 1?
Pairs of homologous chromosomes line up on the equator. Spindle microtubules attach to different homologous chromosomes in each pair by their centromeres so they are drawn to opposite poles. Gentle pulling checks tension and aligns chromosomes
49 of 219
What happens in anaphase 1?
Spindle microtubules shorten to pull homologous chromosomes to opposite poles. This halves the chromosome number. Cell membrane pulled inwards to soon divide the cell
50 of 219
When does the first meiotic division end?
When the homologous chromosomes arrive at opposite poles (telophase 1)
51 of 219
What happens in telophase 1?
Chromatids uncoil. Nuclear membrane reforms around each nucleus.
52 of 219
Which stage is the longest in meiosis?
Prophase 1
53 of 219
Prophase 2 is the same as...
Prophase 1
54 of 219
What is the difference between meiosis 2 and meiosis 1?
Meiosis 1 involves diploid cells, meiosis 2 involves haploid cells as chromosome number already halved
55 of 219
In metaphase 1, how many poles was each centromere attached to?
56 of 219
In metaphase 2 how many poles is each centromere attached to?
2 (both)
57 of 219
What do spindle microtubules attach to?
58 of 219
What is the only difference between metaphase 1 and 2?
The number of poles each centromere is attached to
59 of 219
At what stage do sister chromatids start being called chromosomes?
Anaphase 2
60 of 219
What happens in anaphase 2?
Centromeres divide to pull chromatids to opposite poles. Cell membrane pulled inwards again
61 of 219
What happens in telophase 2?
Chromatids reach opposite poles and nuclear membrane reforms. Chromosomes uncoil and cytokinesis splits cell to form four haploid cells
62 of 219
What is a tetrad/ bivalent?
A pair of homologous chromosomes (4 chromatids)
63 of 219
At what stage is the DNA of a cell replicated?
S stage of interphase before the first meiotic division
64 of 219
If there was a division in meiosis 1, how come there are haploid cells formed at the end of meiosis 1 and meiosis 2?
In meiosis 1, a chromosome is two chromatids but in meiosis 2, a chromosome is 1 chromatid
65 of 219
Meiosis 1 is the separation of...
Homologous chromosomes
66 of 219
Meiosis 2 is the separation of...
Sister chromatids
67 of 219
What are the two ways genetic variation is introduced in meiosis?
Random orientation of bivalents in metaphase 1, crossing over of non-sister chromatids in prophase 1
68 of 219
What does it mean by random orientation of homologous chromosomes?
Homologous chromosomes always stick together but which chromosome faces which pole and attaches to which spindle microtubule could differ and does not affect the orientation of other pairs of homologous chromosomes
69 of 219
Why does random orientation not create genetic variation in meiosis 2?
Consists of single chromosomes with two sister chromatids that are genetically identical
70 of 219
How is crossing over random?
Crossing over could occur anywhere along the length of the chromosome
71 of 219
What is reduction division?
Reducing the number of chromosomes through cell division (meiosis 1 e.g.)
72 of 219
What is a haploid cell?
Half the number of chromosomes
73 of 219
How do you work out the number of combinations of chromosomes formed in random orientation in metaphase 1?
2 to the power of the haploid number
74 of 219
How does crossing over lead to genetic variation?
New combinations of alleles formed in male and female gametes
75 of 219
Crossing over occurs as a part of which process?
76 of 219
What else creates genetic variation other than random orientation and crossing over?
Fusion of gametes is random leading to a wide number of allelic combinations
77 of 219
What is non-disjunction and when does it occur?
Non-separation of chromosomes and can occur in the anaphase 1 or 2
78 of 219
What are the two ways of getting cells for chromosome testing?
Amniocentesis and chorionic villus sampling
79 of 219
How is amniocentesis done?
Insert hypodermic needle through abdomen and uterus wall to draw out amniotic fluid containing fetal cells into a syringe
80 of 219
Where are the chorionic villi?
In the placental chorion
81 of 219
What are the risks of miscarriage with a) amniocentesis and b) chorionic villus sampling
a) 1% b) 2%
82 of 219
Are there any risks of infection from amniocentesis or chorionic villus sampling?
83 of 219
Just because there is a correlation between mother age and Down's syndrome or trisomy occurrence, this doesn't mean...
There is direct causation
84 of 219
What are the ethical implications of testing for chromosomal disorders?
Terminating the pregnancy if there is a disorder (or a specific gender in some cultures) or do you keep going with it?
85 of 219
Mendel's large numbers of pea plants ensured...
Reliability and also repeating his experiments with seven different traits
86 of 219
What is a genotype?
The alleles possessed by an organism
87 of 219
Why do you only have one gamete in a monohybrid cross but two genotypes?
Gamete involves haploid cells with one type of each chromosome but because the plants are diploid, they have two of each gene
88 of 219
If you cross homozygous dominant gametes with homozygous recessive gametes what do you get?
All offspring are heterozygous dominant
89 of 219
What is segregation?
In meiotic division, the two alleles of each gene separate into different haploid nuclei. Separating the alleles into gametes
90 of 219
In a monohybrid cross of two heterozygous dominant genotypes, what is the genotypic and phenotypic ratio?
Genotypic: 1:2:1 Phenotypic: 3:1
91 of 219
How does segregation occur?
Two alleles are located on homologous chromosomes which are pulled to opposite poles in anaphase
92 of 219
What is required for a 3:1 phenotypic ratio to occur?
One allele must be dominant and one recessive
93 of 219
What is the effect of a dominant allele?
Masks the effect of the recessive allele in a heterozygote
94 of 219
What does homozygous mean?
A pair of matching alleles for a particular characteristic
95 of 219
What does heterozygous mean?
An individual or cell carrying non-identical alleles for a particular trait
96 of 219
What causes cystic fibrosis?
Recessive alleles of autosomal genes
97 of 219
What causes Huntington's disease?
Dominant alleles of autosomal genes
98 of 219
What happens with cystic fibrosis?
Presence of recessive allele of chromosome 7 codes for CFTR gene which affects chloride channels in mucous membranes (sweat, mucous and digestive juices)
99 of 219
What must both parents be for a child to get cystic fibrosis?
100 of 219
Why do carriers not get the disease?
They also have the dominant allele to mask the effects of the recessive allele
101 of 219
How does Huntington's disease form?
A dominant allele developed due to a mutation in the HTT gene on chromosome 4
102 of 219
What are some symptoms of Huntington's disease?
Loss of muscle coordination, cognitive decline, psychiatric problems
103 of 219
What does the HTT gene code for?
Huntingtin protein with an unknown function
104 of 219
If only one parent has the gene for Huntington's disease, what is the probability of offspring getting the disease?
105 of 219
What do pedigree charts determine?
The genotype of an individual and if a disease is caused by a dominant or recessive allele
106 of 219
In pedigree charts, how do you represent males and females?
Females with a circle, males with a square
107 of 219
What does a shape with a dot in it mean in a pedigree chart?
They are a carrier
108 of 219
In a pedigree chart, if the disease is present in every generation what does that suggest?
The disease is dominant
109 of 219
Why is sex linkage almost always dependent on the X chromosome?
The X chromosome is bigger and has important genes on it while the Y chromosome is smaller and has less genes
110 of 219
Why are males more likely to develop a sex-linked disease?
If it is due to a recessive allele, females require two recessive alleles to develop the disease but males only require one because the Y chromosome does not carry an allele
111 of 219
Who can be carriers of sex-linked diseases?
112 of 219
Name two diseases based on recessive alleles on sex-linked genes?
Red-green colourblindness and hemophilia
113 of 219
What does co-dominance mean?
If both alleles are present, they both affect the phenotype of the individual
114 of 219
What is meant by multiple alleles? Give an example
More than two alleles for a particular gene. For example, the blood groups have the alles IA, IB and i
115 of 219
How can you get a punnett grid of all blood groups?
Heterozygous IAi crossed with IBi parents
116 of 219
When can you predict offspring ratios?
Large numbers of offspring
117 of 219
Why might a predicted ratio be different to the actual ratio?
One allele combination could be lethal
118 of 219
Are mutations random?
119 of 219
What types of radiation are mutagens?
X-rays, short or medium wave UV, gamma rays and alpha particles from radioactive isotopes
120 of 219
Give examples of mutagenic chemicals
Mustard gas used as a chemical weapon, nitrosamines in tobacco, solvent benzene
121 of 219
Give two examples of nuclear events that can be studied to see the effects of radiation
Chernobyl nuclear accident and Hiroshima nuclear bomb
122 of 219
Why did Chernobyl cause less deaths despite the fact it released more radioactive contents
More radiation (higher doses) was spread over a wider area for longer and isotopes have a longer half-life
123 of 219
What happened at Chernobyl?
Fire and explosions in core of nuclear reactor in Ukraine
124 of 219
Which isotopes/ radioactive materials were released at Chernobyl?
Iodine-131, caesium-134 and caesium-137 as well as uranium and other radioactive metals broke up in the explosions and escaped
125 of 219
How many workers died in Chernobyl? What disease affected workers?
28 within 3 months and leukemia more prominent
126 of 219
What was the effect of radioactive iodine release in Chernobyl?
Milk and drinking water with high levels of radioactive iodine. As many as 6000 got thyroid cancer and many cattle and horses nearby died from damage to their thyroids
127 of 219
What was there bioaccumulation of and in what from Chernobyl?
Radioactive caesium in fish and lamb - consumption banned due to the long half-life of caesium-137
128 of 219
What happened to woodland from Chernobyl?
4km squared of pine forest downwind of reactor went ginger brown and died. In the absence of humans in this area, populations of lynx and wild boar have thrived
129 of 219
How many people died from Hiroshima?
130 of 219
The higher the dose of radiation...
The greater the risk of cancer or leukemia by survivors
131 of 219
What was a main health effect of the Hiroshima bomb?
Mutations leading to many stillbirths and malformations
132 of 219
How did people feel stigmatised after Hiroshima?
Husbands reluctant to marry them for fear their children would get genetic diseases
133 of 219
Is there much evidence of mutations in children who were fetuses at the time of Hiroshima?
134 of 219
How do you define genetics?
The study of variation and inheritance
135 of 219
What is a gene?
A heritable factor consisting of the length of DNA and influences specific characteristics
136 of 219
Where is the gene located for the beta polypeptide of hemoglobin?
Near the end of the short arm of chromosome 11
137 of 219
What has less genes that eukaryotes?
138 of 219
What makes alleles?
A change in the base sequence of one or a vary small number of bases in a gene DNA sequence
139 of 219
What causes the genetic disease sickle cell anemia?
The second base on the sixth codon in the beta polypeptide hemoglobin gene is thymine instead of adenine
140 of 219
What is the name of the beta polypeptide hemoglobin gene?
141 of 219
What codon is normally transcribed, what is the mRNA sequence and amino acid formed in sickle cell anemia?
Normally the codon is GAG, in sickle cell anemia it is GTG leading to GUG on mRNA. This codes for valine instead of glutamic acid
142 of 219
What are databases currently used for?
Storing large amounts of base sequence information from genome research
143 of 219
Why has searching and sharing gene information become easier?
Internet means it can be easily accessed and shared across the world and data can also be searched and extracted easier
144 of 219
What are some uses of gene databases?
Finding the locus of a gene and the corresponding protein it codes for (protein product). Also comparing base sequences of different species to find how many differences there are, how long ago they diverged and the common ancestor
145 of 219
What does PCR do?
Produces many copies of a DNA molecule
146 of 219
Why would you want to do PCR?
If you have only a small sample and you need a larger sample of DNA for analysis
147 of 219
DNA from what can be amplified in PCR?
Blood, semen or other tissue or a long-dead specimen
148 of 219
What is the first stage of PCR?
DNA is heated to 95 degrees celcius to separate the DNA strands
149 of 219
What is the second stage of PCR?
Temperature reduced to 53 degrees celcius to allow primers to bind to both strands of DNA next to the section to be replicated
150 of 219
What is the third stage of PCR?
Temperature increased up to 73 degrees celcius to encourage Taq DNA polymerase to replicate both strands, starting at the primer and producing two-double stranded copies of the original DNA sequence
151 of 219
What does gel electrophoresis do?
Separates mixtures of proteins of DNA fragments
152 of 219
How does gel electrophoresis work?
Thin sheet of gel acts as a molecular seive. The mixture of proteins or DNA is placed over/in the gel and an electrical charge applied with electrodes at either end. DNA is negatively charged so will move to the positive electrode.
153 of 219
What sort of fragments move faster through the gel in gel electrophoresis? Why?
Smaller fragments because there is less resistance
154 of 219
What is the human genome project?
Research to find human genomes (DNA sequence or genes that comprise a human)
155 of 219
What is the human genome project allowing the study of?
Genetic variation
156 of 219
What has the human genome project led to?
The plant genome project to find genomes of 1000 plants, also found 100 prokaryote genomes and eukaryote genomes and other species
157 of 219
What are short tandem repeats?
Shorter DNA sequences of 3-5 bases repeated many times instead of one long sequence
158 of 219
Where are short tandem repeats used?
DNA profiling
159 of 219
What is specifically looked at in DNA profiling?
Short tandem repeat alleles as there could be many different alleles possible at that chromosome locus
160 of 219
What is a requirement for the DNA used for DNA profiling?
Must not be contaminated by anyone or something else's DNA
161 of 219
What is done with the DNA for DNA profiling?
A selection of short tandem repeat loci are found and copied with a PCR. The copies of alleles are separated with gel electrophoresis to give a pattern of bands
162 of 219
How many loci are used for DNA profiling?
163 of 219
Why do they use multiple loci for DNA profiling?
Unlikely for individuals to have identical base sequences and alleles for the more loci there are
164 of 219
In the gel electrophoresis for DNA profiling, when might two individuals have the same pattern of bands?
Identical twins
165 of 219
As well as for forensic purposes, when else is DNA profiling used?
Paternity testing
166 of 219
When were the first DNA profiling techniques used? What was discovered?
Enderby double murder case showed the DNA from the semen of the culprit did not match the prime suspect DNA who confessed to the murders so he was innocent
167 of 219
How can you use DNA profiling for forensic analysis?
Use as evidence in court cases and to eliminate or prove the prime suspect is guilty
168 of 219
What are the three stages of PCR called?
1) Denaturation 2) Annealing 3) Extension
169 of 219
What sort of amplification is PCR?
Exponential amplification
170 of 219
What sort of enzymes are used in DNA profiling to chop the short tandem repeats into small sections before gel electrophoresis?
Restriction enzymes (endonucleases)
171 of 219
What are the names of organisms that have had a gene transferred to them?
Genetically modified organisms or transgenic organisms
172 of 219
What does a vector do in genetic modification?
Carries the DNA
173 of 219
What is the vector in the transfer of insulin genes to bacteria?
174 of 219
What is a recombinant plasmid?
A plasmid with a gene inserted from another species
175 of 219
What is a host cell in genetic modification?
The cell that receives the new gene
176 of 219
What allows genetic modification and gene transfer?
Universality of the genetic code
177 of 219
What is extracted from human pancreas cells for genetic modification?
mRNA coding for insulin
178 of 219
How is the mRNA coding for insulin converted to DNA?
Reverse transcriptase enzyme
179 of 219
Sticky ends composed of which base are made in the DNA section?
G nucleotides
180 of 219
Sticky ends composed of which nucleotide are made in the plasmid?
C nucleotides
181 of 219
How are plasmids cut open at precisely defined locations?
Restriction enzymes (endonucleases)
182 of 219
What happens once the preparation of plasmid and insulin genes are complete?
They are allowed to mix together and complementary base pairing links the sticky ends together
183 of 219
What is the role of DNA ligase in genetic modification?
Makes sugar-phosphate bonds to seal up nicks in the DNA once plasmids and genes have combined
184 of 219
What happens when recombinant plasmids are mixed with host cells?
The E.Coli absorbs them
185 of 219
How is insulin produced from the E.Coli?
The bacteria is cultured in a fermenter and starts to make insulin which is extracted and purified to be used by diabetics
186 of 219
What quality is the insulin in when it is produced by E.Coli?
High purity and reliability
187 of 219
How has genetic modification been used for crops?
A gene from a bacterium has been transferred to Bt maize. It codes for a protein called Bt toxin which kills any insect pests that feed off the plant e.g. corn borers
188 of 219
What other genetic modification of plants has taken place?
Herbicide resistance, increased vitamin content, resistance to viral diseases, decreases allergen or toxin content, increases tolerance to drought, cold or saline soils
189 of 219
What are the benefits of Bt maize?
Increased yield so more food and less pests; Less land for crops needed so some for wildlife conservation; less use of insecticide sprays which are expensive and harmful to workers or wildlife; lowers levels of toxic and carcinogenic mycotoxins
190 of 219
What environmental benefit not mentioned yet is there from Bt maize?
Produces a cleaner, better environment because less pesticides are going into lakes and rivers (eutrophication). Cost of crop production reduced because less pesticides needed
191 of 219
What are the risks of Bt maize?
Could harm other animals if toxin pollen gets to wild plants and those organisms feed on it (caterpillars and monarch butterfly). Detritivores also at risk. Could make wild plants toxic through cross pollination. Pests could get resistant
192 of 219
What risks are there of Bt maize in terms of human health, organic growers, biodiversity and wild plants?
Humans could be allergic. Pollen with toxin could cross pollinate neighbouring organic plants, leading growers to lose their certificate and not get premium price for produce. Reduced biodiversity of insects and 'superweed' formation
193 of 219
What is a natural form of cloning?
Asexual reproduction
194 of 219
Give examples of asexual reproduction leading to cloning?
Plants produce tubers, runners, extra bulbs or other structures. Aphids give birth to young formed asexually from their own cells
195 of 219
What is the simplest method of cloning?
Break up an embryo at early stage into multiple groups of embryonic stem cells which develop into genetically identical individuals
196 of 219
What is the drawback of the simplest cloning method?
Do not know what characteristics organism will develop to have
197 of 219
Name another method of cloning
Somatic-cell nuclear transfer
198 of 219
What is a clone?
A group of genetically identical organisms derived from a single original parent cell
199 of 219
Which cell nucleus is used to make Dolly?
200 of 219
Why is the udder cell to make Dolly cultured for 6 days?
To make it undifferentiated so it would not form an udder cell again
201 of 219
What other cell is used to make Dolly? What happens to it?
An unfertilised egg cell has its nucleus removed
202 of 219
How are the donor nucleus and egg cell fused together?
A pulse of electricity which also stimulates it to divide
203 of 219
Which sheep is Dolly genetically identical to?
The sheep with the udder cell taken (nucleus used to make Dolly)
204 of 219
Why is Dolly not completely genetically identical to the udder cell mother sheep?
The egg cell contains mitochondrial DNA. The enucleated egg contributes cytoplasmic contents and organelles to the cloned embryo
205 of 219
Why is it hard to clone adult animals?
Cells are at an advanced stage of differentiation so fusion does not necessarily lead to embryos
206 of 219
What is a method of cloning plants?
Stem cuttings
207 of 219
How do stems produce roots from a stem cutting?
When base is placed in water or a solid medium
208 of 219
What could be the independent variables in a stem cutting investigation?
Whether a rooting powder is used, a plastic bag is over the cutting, how many leaves are on the cutting, how warm the cuttings are, age of plant, light, species of plant
209 of 219
What could be the dependent variable of a stem cutting investigation?
If roots form or not, how many roots form, length of longest root, number of days before rooting occurs,
210 of 219
What could be a control variable in a stem cutting investigation?
Same species of plant
211 of 219
How should a stem cutting investigation be carried out?
Cut a cutting off the parent plant just below a node. Place in a well-aerated and moisture-retentive compost and place a plastic bag over the cutting
212 of 219
Why would you place a plastic bag over a cutting?
Increase humidity to decrease transpiration
213 of 219
What is the actual name for cloning plants using stem cuttings?
Artificial propagation
214 of 219
What is a node on a stem?
A meristematic zone
215 of 219
What were Mendel's three laws?
Law of segregation, law of independent assortment, law of dominance
216 of 219
What was Mendel's law of segregation?
Inherited traits are controlled by a pair of alleles which are separated during meiosis to give one allele of each gene in a sex cell. Alleles are passed from one generation to the next as distinct units
217 of 219
What is Mendel's law of independent assortment?
The inheritance of one characteristic is independent of the inheritance of another. The separation of alleles of one gene is independent of the separation of other alleles in gamete formation
218 of 219
What is Mendel's law of dominance?
An organism with two dissimilar alleles will express the one that is dominant
219 of 219

Other cards in this set

Card 2


What are the shapes of the DNA molecules in eukaryotes?



Card 3


Do eukaryotes have plasmids?


Preview of the front of card 3

Card 4


What is the difference between eukaryote and prokaryote DNA in terms of proteins associated with it?


Preview of the front of card 4

Card 5


How many chromosome do eukaryotes have?


Preview of the front of card 5
View more cards


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Genetics resources »