Which statement is faoyaknr -pb)d4b* 4:vdlse about the genome?

  Which of the following correctly pairs changem-;pq v,qx 8rss in the rate mRNA is degraded in the cytoplasm with the effect on the rate polypeptides for the corresponding gene xq,-;rp8mv q sare synthesised?

  Which of the followinl -xd; twpr v23v *t8amk,9rghg best defines the term “Proteome”?

  Which of the following statements is / are correct regarding the epigen iid;m ..cm.a bv.ene7etic regul dm7ce..nbiia; ..mve ation of gene expression?
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 structure of thej 4:bkeqn*lzz1g7c 4m 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 ,uk)frvs(bl1m fut* ; ojm./egenome, transcriptome and proteome of monozygotic twins may diffeuu( b/o1vkrmeff* ;j.,t ) lsmr?
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 and s9d3w4ntf9eu u9c2h.fvojtp c xd u0(4 pecialised cells is/are not true4o djfvf nwct uuhx9d3(p4990.t2cue ?
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 sometimesx 4 s6s9s qyursa31)r4ozdti 6e,ytt( reduced in response to environmental stimuli. How might this mechanism of producing6 49 ro3q ydst,( uat6)t4xssezisy r1 more polypeptides for a given gene increase an individual's fitness?

1.Outline the role of gene expression in stem growth. vdi+iehi9jte j*5puhe* . 8i+

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

3.Explain the process and applications of micropropagation.

  Ligers are the offspring4kvu6 1acw4y,xyl*qs/aa npj)m4 p9k of a male lion 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 explanation for the large size difference between a liger in comparison to thek1 pya4y9xj kwlacpn)/64 4a,m*uvs q parents?

The graphs show the results from a long-term study on 86 pairs of monozy 8e;hd4anp65sc ;bkli gotic twins, ov;hci4p85en s ladb ;6ker 80 years.



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 expressfyyc,oof1c;w 6 :1qjyed in the brain are understood to have an important role in feeding behaviour and the study of this is important in order 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 yj 6oycof1 :;1wqcyf,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 gene expressihoal/f6f35ra vb-v6o. rr o +qon. DNA methylation patterns can change in identical twins who are exposed to different environmev/l63fhrv o6qb+f5aao-ro.rntal 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 impo+ er k3vlqlzbcx79cgek vk1 l5:(:sj 7rtant for cell differentiation and the development of an organism. For example, the developmental pattern of a common fruit fly (Drosophila melanoga e1l5:r zskv(9cg7 qbe:lkxljk7v3c+ster).

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 mea mzaj pn z0/.r9+h 1pw3edehq63xsa 9an percentage similarity between monozygotic and dizygotic twins and also between brothers in terms of their genomes, transcriptomes and proteomes. Monozygotic twihs+3 a pmn.j3qze0h99 1/6a earwdzxpns 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.