Which statement is fa,t6tln cy/ 9tklse about the genome?

  Which of the following correctly pairs changes ipdp) t59gw /qjn the rate mRNA is degraded in the cytoplasm with t9 /pqwjgt d5)phe effect on the rate polypeptides for the corresponding gene are synthesised?

  Which of the following best defines the term unjhl+:d - bdwj1lc/yff-w+nv. .0y l“Proteome”?

  Which of the following statements is / are correct regardingzygim3dt13,ql6s -y nht f82 g the epigenetic regulation of gene expt8 36ndsym t2l 1-3zhg gyf,qiression?
I. The base that undergoes most frequent methylation is adenine.
II. Gene transcription is inhibited by methylation of DNA
III. Methylation of histones only causes activation of transcription

  The diagram below represents the structuw+9 ge-bauj+--k/wvpk c ajd1 re of the protein haemoglobin.

1.1.State the function of haemoglobin.
Haemoglobin is a protein found in red blood cells which transports    around the body
1.2.Describe the structural differences that distinguish one protein from another.

2.Haemoglobin is part of an organism’s proteome. Define proteome.

3.Describe how the structure of a named protein, other than haemoglobin, is related to its function.

4.1.Explain the impact high temperatures can have on the structure and function of proteins such as haemoglobin.

4.2.State another abiotic factor which can impact the structure of a protein.

  Which are correct explanations of why the genome, transcriptox9j;x4 rhd4r sme and proteome of monozy4rs h4dx;r 9jxgotic twins may differ?
I. The genome of two monozygotic twins will differ only due to random mutations as each individual grows and develops from a zygote into an adult.
II. The genome, transcriptome and proteome of two monozygotic twins are the same.
III. The transcriptome and proteome of monozygotic twins differ mostly due to environmental facts which affect gene regulation.

  Which statements about embryonic stem cells and70tl m 0nz1mly:lf-z b specialised cells is/are not true?z0zny7: tmlb fm10l -l
I. Embryonic stem cells have higher levels of DNA methylation than differentiated cells
II. Specialised cells are more differentiated than embryonic stem cells
III. Most specialised cells and embryonic stem cells both contain the entire genome of an organism

  The rate mRNA is degraded in the cytoplasm is somet w,c3q sn0dh6wimes reduced in response to environmental stimuli. How might this mechanism of producing more polypeptides for a given geneqn ,s0w hd36wc increase an individual's fitness?

1.Outline the role of gene expression in stem 1ge/juubf +9k growth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  Ligers are the offspring of a male lik 9 rz;w,6negpgw 6*bb.j qf: g.mt*qion and a female tiger. Tigons are the offspring of a female lion and a male tiger. Ligers tend to be much larger and heavier than their parents, while this is not usually seen with tigons. What is the best gpbeg*6*k6m jw . .bi f:;9 grq,qzwtnexplanation for the large size difference between a liger in comparison to the parents?

The graphs show the results from a long-tu(w:vy6 er2 lx h-+wudd95srrerm study on 86 pairs of monozygotic twins, over 80 yeur dr6y9d:r+5s ewl- uv h2xw(ars.



1.Describe the relationship between the percentage similarity in DNA methylation pattern and age.

2.Explain the relationship that you referred to in part (a).

3.Explain the effect that DNA methylation most likely has on gene expression.

4.Explain why monozygotic twins were used in this study.

5.Suggest one limitation of conducting a study in humans over 80 years.

6.Evaluate whether this study provides evidence that decreases in the percentage of DNA methylation is a predictor of an early death.

7.Distinguish between the genome and the epigenome.

  Appetite regulating genes expressed in the brain are ynx5f7g:n q1jk: l z1cunderstood to have an important role in feeding behaviour and the study of this is important in order zlc xn: f1q:5g1kj7yn to understand the underlying causes of feeding disorders. However, other areas, outside the brain, such as the gastrointestinal tract, are receiving attention for their potential influence in the regulation of appetite.

In a study, scientists investigated the expression of appetite-regulating genes in the gut, using zebrafish (Danio rerio) as a model organism.

In their first experiment, a variety of feeding conditions were applied to wild type zebrafish and the expression of different genes, known to have a role in appetite regulation, were measured.


1.Identify the gene and feeding condition which show the greatest difference in relative fold change in expression compared to the control.

2.Describe the effect of feeding conditions on the expression of the galr2a gene.

3.Calculate the increase, as a percentage, in the relative fold change in expression between the control feeding condition and the fasted feeding condition for the gene cnr1. The percentage is   %

4.State the name of the gene which had the greatest increase in expression when zebrafish were fed every 2 hours.The name of the gene is   .

In a second experiment, scientists used a zebrafish mutant, which, unlike the wild type, had impaired leptin receptors, due to a mutant gene lepr. The same feeding conditions were then applied and the expression of the same genes were measured.


5.1.Compare and contrast the effect of feeding conditions on the expression of the apln gene in wild type and mutant zebrafish.

5.2.State which feeding condition, other than the control, had the most similar results for wild-type and lepr-mutant zebrafish for the gene scg2a.

A final experiment was conducted to test the effect of a variety of known appetite suppressing agents on the feeding volume of zebrafish, as a precursor to studying their effect on gene expression.
In the experiment, paramecia were fluorescently labelled and fed to zebrafish, with transparent body cavities, which were treated using an appetite suppressing agent. Using a 96-well microplate reader, scientists were able to measure the intensity of fluorescence in zebrafish as a measure of the volume of paramecia they consumed. The experiment and its results are outlined below.



6.1.State the name of the agent which, at a concentration of 3.3µM, resulted in zebrafish having the poorest appetite.
   resulted in the zebrafish having the poorest appetite.
6.2.Suggest why there are no results for Mazindol at a concentration of 10µM.

7.Approximately 70% of the coding genes of zebrafish are related to humans, and about 84% of human genes associated with disease are related to zebrafish. Evaluate the use of zebrafish in the study of obesity in humans.

  DNA methylation has an important function in geneqi2gaiaih8; ,fcv.b7 expression. DNA methylation patterns can change in identical twins whha 7iqicv8,fi2ga.; bo are exposed to different environmental conditions.

Which of the following environmental factors would have an impact on DNA methylation in identical twins?
I. Mutations of gene
II. Type of diet
III. Lifelong physical activity

  Gene regulation is important for cell differentiation an:ebiqaaa8 w 6 wiau00:d the development of an organism. For example, the developmental pattern of a common fruit fli:8 aau waeqib w00:a6y (Drosophila melanogaster).

Which of the following play a direct role in regulating gene expression?
I. Enhancer
II. Repressor
III. Epigenetic modifications

The table below shows estimates of the mean percentage s tiht8ph2el+9;uq e kg0y+8 hsimilarity between monozygotic and dizygotic+hs0i kh89yqte +hpu2l 8;egt twins and also between brothers in terms of their genomes, transcriptomes and proteomes. Monozygotic twins result from the fertilisation of one egg by one sperm. The resulting embryo later divides into two embryos. Dizygotic twins result when two egg cells are fertilised by two different sperm cells.

1.Explain why it is important for different cells in multicellular organisms to have different proteomes.

2.Describe how methylation can influence gene expression.

3.Explain why the mean per cent similarity decreases from the most similarity between genomes to the least similarity between proteomes.

4.With reference to the data in the table, discuss the similarities and differences in mean per cent similarity between the dizygotic twins and the brothers.