Frage 1
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What are promoter regions of DNA?
Antworten
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Gene regulatory elements that tell RNA polymerase to perform transcription.
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Gene regulatory elements that tell DNA polymerase to perform transcription.
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Gene regulatory elements that tell RNA polymerase to perform translation.
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Gene regulatory elements that tell DNA polymerase to perform translation.
Frage 2
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Transcription factors bind to regulatory sequences and cause what?
Frage 3
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What does the green question mark represent?
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Nucleosome
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Chromosome
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Telomere
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Promoter region
Frage 4
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The green arrow is pointing to what?
Frage 5
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The nucleosome is made up of what components?
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Histone octamer of H2A, H2B, H3 and H4.
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Core DNA
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Linker DNA
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Histone tetramer of H2A, H2B, H3 and H4.
Frage 6
Frage
SRY is a transcription factor on the Y chromosome. It's absence/mutation leads to...?
Antworten
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Absence of the male phenotype, leading to production of a female phenotype.
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Absence of the female phenotype, leading to production of the male phenotype.
Frage 7
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The Y gene of the XY male genotype is gene-poor. What are two dosage compensation mechanisms that could help to equal gene expression levels in both males and females.
Antworten
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Upregulation of transcription of the X male chromosome
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Inactivation of one of the X female chromosomes
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Addition of an extra X chromosome in the male XY genotype
Frage 8
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Epigenetics produces multiple phenotypes from the same genotype.
Frage 9
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Diploid cells have a single copy of an allele.
Frage 10
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Autosomal conditions are genetic conditions that occur on non-sex chromosomes.
Frage 11
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An X-linked condition will only affect the phenotype of a female if the copies of the allele on each X chromosomes are abnormal.
Frage 12
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Achondroplasia (dwarfism) is what type of condition?
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Autosomal dominant
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Autosomal recessive
Frage 13
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Albinism is what type of condition?
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Autosomal recessive
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Autosomal dominant
Frage 14
Frage
How might a child have achondroplasia despite the parents not having it?
Frage 15
Frage
How can two parents that have albinism have a child without albinism?
Antworten
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Albinism is autosomal recessive. This means that any child born to parents who both have albinism should also have albinism as there are no dominant traits in the parents as their genotypes are both homozygous recessive. The reason for the absence of albinism is because the mutated copies in the parents could differ in that the fathers two copies could inhibit a different enzyme in the metabolic pathway that leads to lack of pigment than the mothers. The child will inherit one copy from the father and one copy from the mother and therefore only 50% of each originally fully mutated pathway is inhibited and thus may still be able to produce sufficient melanin.
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Albinism is autosomal dominant. This means that any child born to parents who both have albinism should also have albinism as there are no dominant traits in the parents as their genotypes are both homozygous dominant. The reason for the absence of albinism is because the mutated copies in the parents could differ in that the fathers two copies could inhibit a different enzyme in the metabolic pathway that leads to lack of pigment than the mothers. The child will inherit one copy from the father and one copy from the mother and therefore only 50% of each originally fully mutated pathway is inhibited and thus may still be able to produce sufficient melanin.
Frage 16
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Haemophilia results in blood clotting problems due to factor 7 deficiency.
Frage 17
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Females are more likely to suffer from haemophilia
Frage 18
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Phenylketonuria is a disorder resulting from the production of phenylketones due to mutation in what enzyme?
Frage 19
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What are some causes of variation?
Frage 20
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How many pairs of autosomal chromosomes do most humans have?
Frage 21
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Mitosis is important for what?
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Growth
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Repair
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Tumour growth
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Spermatogenesis
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Oogenesis
Frage 22
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What is crossing over?
Frage 23
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What is independent assortment?
Frage 24
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When does independent assortment occur?
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First meiotic division
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Second meiotic division
Frage 25
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Chromosomal non-disjunction describes the failure of homologous chromosomes to seperate in the first or second division in meiosis or during mitosis.
Frage 26
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Chromosomal non-disjunction can lead to trisomy of sex chromosomes.
Frage 27
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The following picture shows the process of meiosis in males
Frage 28
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The following picture shows chromosomal non-disjunction of the...
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First division
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Second division
Frage 29
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The following picture shows chromosomal non-disjunction during female meiosis.
Frage 30
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Meiotic non-disjunction occurs pre-embryonically and therefore all cells are effected.
Frage 31
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Mitotic non-disjunction occurs during embryonic division so there may be a mix of normal and abnormal cells, resulting in an abnormal conceptus.
Frage 32
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How does trisomy 21 (aka Down's) occur?
Antworten
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One copy of the mother's C21 translocates to C14. Upon fertilisation, the future child will have inherited two copies from the mother (due to the translocated C21 to C14 as well as the normal C21 copy) and a copy from the father, making 3 copies of C21.
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The mother is a carrier of three C21 copies which leads to the child inheriting two copies of C21 from the mother and one from the father.
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C14 changes into C21 upon fertilisation, therefore two copies are inherited from mother/father and one other copy from the father/mother.
Frage 33
Frage
Mutations are frequently due to...
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Copying errors during DNA replication
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Spontaneous depurination
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Background ionising radiation
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Chromosomal non-disjunction
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Splicing errors
Frage 34
Frage
A transcriptional mutation commonly affects the promoter region of a gene, therefore promotion to initiate transcription does not occur and thus a protein is not produced.
Frage 35
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A splice site mutation (deleted/creation of splice site) does not introduce introns into the mature mRNA transcript.
Frage 36
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Common gene mutations are indicated in certain cancers.
Frage 37
Frage
What is the function of the mismatch repair machinery?
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The mismatch repair machinery helps to repair slippaged DNA (insertion/deletions) that escapes proofreading
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The mismatch repair machinery helps to destroy cancer cells
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The mismatch repair machinery helps to repair incorrectly paired DNA strands
Frage 38
Frage
Sickle cell is caused by a substitution of hydrophilic valine for hydrophobic glutamate (GAG -> GTG)
Frage 39
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Cystic fibrosis is caused by deletion of a codon coding for a phenylalanine residue of the CFTR channel protein.
Frage 40
Frage
PCR are repeated cycles of...?
Antworten
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Primer, Polymerase, Denaturation.
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Polymerase, Primer, Denaturation.
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Denaturation, Polymerase, Primer.