Practise IB Biology HL D2.2 by tracing gene expression, transcriptional control and epigenetic regulation from DNA activity to cell-specific proteins and phenotype.
24 questions in this syllabus scope, with question parts counted together.
117 papers analysed · Tagging incomplete
Promoters are non-coding regions in DNA. What is the role of a promoter?
It starts translation.
It starts mRNA splicing.
It is a binding site for DNA polymerase during DNA replication.
It is a binding site for RNA polymerase during transcription.
What is a consequence of nucleases binding to mRNA?
Transcription stops.
mRNA binds to ribosomes.
More mRNA is synthesized.
mRNA cannot be translated again.
No public sample questions are available for this syllabus point yet.
Which statement correctly describes genome and proteome?
Only the genome but not the proteome can be analysed using gel electrophoresis.
The genome and the proteome are the same in all tissues in an organism.
In cells of different tissues, the genome is the same while the proteome varies.
Only mutations in the proteome but not in the genome cause any variability.
Scientists measured methylation levels of amino acids in chromosome 2 in twin studies.
The methylation levels of twin 1 were significantly and consistently higher than those of twin 2 . What could be proposed to explain this data?
Modification to the histone of twin 1
Removal of the histone from the chromosome in twin 2
The DNA base sequence of twin 1 was altered
Cytosines in promoters of twin 2 are more methylated than in twin 1
No public sample questions are available for this syllabus point yet.
How can environmental factors affect the expression of genes?
By promoting the replication of nucleosomes
By inactivating epinephrine
By making specific changes to the base sequence of genes
By causing the pattern of DNA methylation to be changed
Very soon after fertilization, parental epigenetic methylation is reversed in the DNA. Later, tissue-specific epigenetic modifications are made to the embryonic DNA. The graph follows the degree of methylation from different sources during embryonic development.
According to the graph, what are the changes in DNA methylation during embryonic development?
Only the paternal DNA becomes demethylated.
The maternal DNA becomes demethylated first.
The methylation patterns of the parents' DNA are erased before fertilization.
The methylation patterns of both parents are erased after fertilization.
A study was conducted into the influence of genetic factors on occasional cocaine use, abuse and dependency. Pairs of female twins were interviewed to determine if either or both of them had used cocaine at all and also whether they had become abusers of cocaine or dependent upon it. Abuse was diagnosed if cocaine was having harmful consequences on the life of the person and dependence by signs that the person would suffer withdrawal symptoms without it. For each of these three stages of cocaine use, concordance rates were calculated for both identical and non-identical twins. The concordance rate is how many pairs of twins are both at a particular stage, expressed as a percentage of the total number of pairs in which either or both are at that stage. The bar chart shows the results.
Identify which stage of cocaine use shows the least percentage difference between identical twins and non-identical twins.
Compare the results for identical twins and non-identical twins.
Analyse the data to find whether it supports the hypothesis that genetic factors cause some people to have a much higher chance of cocaine dependence than others.
The diagram shows a nucleosome from the nucleus of a eukaryotic cell.
Explain the role of lactose in the expression of the gene for lactase production.
