WorksheetsMIC1008 Tutorial 13 Nov 2024
Total questions: 15
Worksheet time: 39mins
What are exons?
Set of genes that are adjacent to one another in the genome and are coordinately controlled
Genetic information coding for an amino acid sequence that will form a functional polypeptide/protein
Intervening non-coding segments of DNA
Site where repressor proteins bind
What is the role of promoter region in the regulation of gene expression?
Alter gene expression by binding transcription factors
Bind negative regulators to inhibit gene expression
Recruit RNA polymerase and transcription factors to DNA
Allow for alternative splicing and recombination of genetic components
During transcription of a eukaryotic cell, what determines the template strand (of DNA)?
The location of the AUG start codon
The location of the MET start codon
The base sequence of the enhancer
The base sequence of the promoter
Colour blindness is an X-linked recessive trait. A man and a woman, each of whom has normal vision, have two children, one of whom is colour blind. Which of the following statement is true?
The colour-blind child received the allele for colour blindness from its father
The colour-blind child must be male
Daughters of this couple have a 0.5 chance of being colour blind
If the couple have another child the chance that it will be colour blind is 0.5
What is the first stage of meiosis during which a cell is considered haploid?
Metaphase I
Anaphase I
Prophase II
Telophase II
During translation, which site in the ribosome allows for tRNA molecules to enter the complex?
A site
P site
E site
R site
A mitochondrial disorder exhibits variable severity among siblings, even though they all inherited the mutation from their mother. What is the most likely explanation for this variation in symptom severity?
Random assortment of mitochondrial DNA during meiosis leads to different levels of mutation inheritance among siblings
The severity of the disorder depends on the father’s mitochondrial DNA contribution
Heteroplasmy results in different proportions of mutated and normal mitochondria in each sibling
Mutations in mitochondrial DNA are corrected at varying rates in different family members
Which of the following is a recognized mode of alternative splicing?
Exon skipping
Alternative acceptor site
Alternative donor site
All of the above
If the mRNA sequence is AGA UUU CGA GCC, what are the anticodon of corresponding tRNAs?
Red snapdragons were crossed with white snapdragons. All of the offspring (F1) were pink. When these pink snapdragons were allowed to interbreed, three phenotypes were observed in the second generation in a ratio of 1 red : 2 pink : 1 white.
It is reasonable to conclude from these data that
both of the parental snapdragons are heterozygous
two gene loci are involved in determining the colour in these crosses
a backcross of the F1 pink snapdragons to the red parent would produce red and pink snapdragons
this is an example of recessive epistasis
In a certain plant the production of red pigment for flower colour is achieved by a series of biochemical reactions the last three of which are detailed.
The production of the enzymes is controlled by three independently assorting autosomal genes. The
presence of the enzyme in each case is the dominant phenotype.
Substance X is colourless, substance Y is yellow and substance Z is orange.
It may be predicted that plants of the genotype
XX ; YY ; Zz will have yellow flowers
Xx ; yy ; Zz will have yellow flowers
xx ; yy ; ZZ will have orange flowers
Xx ; Yy ; zz will have red flowers
Imagine that a single nucleotide mutation occurs in the CFTR gene, which encodes a protein that functions as a chloride channel in cells. The mutation changes an adenine (A) to a thymine (T) within the coding region of the gene.
(a) Describe three types of single nucleotide mutations (silent, missense, nonsense) that could occur as a result of this change. Briefly explain how each type of mutation might impact the CFTR protein function.
(b) Can a single nucleotide mutation in the CFTR gene lead to no observable effect on protein function? Explain why this might happen and under what conditions it would occur.
A laboratory is studying the PAH gene, which produces the enzyme phenylalanine hydroxylase, essential for breaking down phenylalanine in the body. A mutation in this gene can result in the disease phenylketonuria (PKU).
a. Explain two types of mutations that are most likely to result in a nonfunctional phenylalanine hydroxylase enzyme.
(b) Explain why a frameshift mutation near the beginning of the PAH gene is likely to have a more severe effect than one occurring near the end.
