Category: Biology

If you start with a single copy of template DNA, how many copies would you have after 10 cycles?

Why do we need two primers in PCR?

In a PCR reaction, the DNA is heated at the start of the cycle to around 95 degrees C. What is the reason for this?

Sometimes, two marker genes are used: The first marker gene is often an antibiotic resistance gene to show if the plasmid is present; the bacteria can only grow on a plate containing the antibiotic, if they have the antibiotic resistance gene on the plasmid. The second is often a gene with a colour change, which is broken by the insertion of the fragment.

e.g. An example of a gene to test for the presence of a fragment is Green Fluorescent Protein (GFP) glowing or not. What would a bacterial plate look like that contained an antibiotic, and was spread with bacteria which had been transformed with a plasmid and had a new gene fragment in?

Sometimes when trying to find a gene which important in a particular disease, it is useful to find out what genes the diseased cells have used (expressed) by extracting mRNA rather than DNA. However, mRNA cannot be used in genetic modifications. What do we need to change it into to be able to use it?

What substances can be used to take mature, differentiated adult cells, and de-differentiate them back into pluripotent stem cells ?(usually only found in embryos).

Which type of stem cells are not found in adults?

What do we call a transcription factor that 'turns on ' genes?

The mRNA travels to the ribosome, where it feeds between the two subunits, exposing the template bases. tRNA molecules each carry a specific amino acid at the top, with a complementary sequence of three bases called an anti-codon at the bottom. The tRNA anticodons then complementary base pair with the mRNA codon. In the ribosome there are 3 binding sites for tRNA, two where a peptide bond is formed between the carried amino acids.

These amino acids then form a ____10_____ chain which leaves the ribosome. The third site is a departure site, where the tRNA which has released its amino acid departs to pick up a new amino acid. Once the entire mRNA sequence has been ____11____, it can either pass into another ribosome to make another polypeptide or be degraded.

What is the removal of introns called?

What is the difference between mRNA and pre-mRNA?

Long term exposure to Oestrogen can increase the risk of developing breast cancer. The exact mechanism is still not fully understood, but which of the following is definitely NOT a suggested mechanism ?

Methylation of DNA is when a methyl group ( CH3) is added onto CpG bases ( cytosine and guanine next to each other). This can stop DNA polymerase from binding.

What effect will increased methylation (Hypermethylation) have on transcription?

Cancer is often caused by a mutation causing a cell to divide uncontrollably and spread into other tissues. Name the gene that normally increases cell division:

Fill in the missing word : Causes of Mutations A mutation is any change to the order of __12___ in the genetic code. These occur naturally as the enzyme _____13_____ replicates the DNA and makes mistakes.

The incidence can also be produced due to exposure to certain agents called mutagenic agents. These can be chemicals such as nitrous acid, which converts cytosine to uracil. Nitrous acid would therefore cause a __14___ mutation. Ethidium Bromide is used to stain DNA during gel electrophoresis. It can insert between bases, acting in a similar way to an addition mutation and therefore causing a __15___ along the rest of the gene.

UV radiation is also a mutagenic agent. It can cause bonds to form between pyrimidine bases ( thymine and cytosine). This bonding causes polymerases to misread or stop working all together at that point.

Which type of mutation will not cause a frameshift?

What is the position of gene on a chromosome called?

Which of the following is not coded for by a gene?

If a template strand has the code starting at the 5 prime end with 5' GCTAAGCA 3'. What would be the order the bases would be added to the new strand ?

Which component of a nucleotide contains nitrogen atoms?

What is lichen made out of ?

What is the biological meaning of succession?

Which method would you use to see if there is a difference between the percentage cover of moss on the north face compared to the south face of tree trunks?

True or False : Two different species cannot occupy the same niche?

Which type of selection is shown by Darwins finches, where small and large beaks were both at an advantage due to different food sources?

Natural Selection is when organisms which are better adapted are more likely to survive and pass on their genes. Factors which affect the chance of survival are called selection pressures. These can be positive ( advantageous) or negative ( disadvantageous). Which of these is a negative selection pressure?

Which of the following is not a cause of variation?

In the creation of gametes, which process mixes up the alleles?

Tay Sachs is a recessive disease which leads to the build up of certain lipids which eventually become toxic. The Cajun community in the USA has an incidence of about 1 in every 3,500 births. What is the allele frequency of the normal healthy genes?

In peppered moths, having light coloured wings is dominant. In Sheffield (an industrial northern town in the UK) a sample of moths was taken. The numbers collected were 73 light coloured , and 326 dark coloured. What proportion of all alleles are for the dark one?

A group of organisms of the same species living in a particular area at a particular time' is the definition for what?

In the actual ratio of 6:1:1:6, there were more of the ginger and black eyed hamsters and more of the white with red eyed hamsters than expected. Therefore, there are proportionately fewer of the mixed traits (Ginger and red eyes and white with black eyes). What process allowed those few mixed trait offspring to occur?

How can you tell if two alleles are autosomally linked?

What is the probability of a colour- blind father and a homozygous dominant female having a colour blind child?

Which type of allele tends to be sex linked?

Marfan Syndrome ( TGF Beta) is dominant (T) to the healthy recessive allele(t) . Having a V shaped hairline (V) is dominant to having a straight hairline (v). What proportion of the offspring of a heterozygous father (TtVv) and a heterozygous mother (TtVv) will be health and have a V shaped hair-line ?

Marfan syndrome is a dominant inherited disorder, where the suffer develops an increase in a growth factor ( TGF - beta) which effects connective tissue. What is the probability of a healthy mother and a heterozygous father having a healthy child?

What is the definition of 'phenotype'?

What is a gene?

Name the molecule that carries out the function : Attaches to the Z line at the end of the sarcomere.

When light falls on cells 1 and 2, only one spot of light is seen. But, when light falls on cells 2 and 3, two spots of light are seen. Say why?

Layer B is the layer which contains the photoreceptor cells. What is it's name ? ( Type your answer).

When the layers of connective tissue are pressed, what happens to the neurone membrane?

The table shows the results on investigating how fast an anaesthetic works. Using the results from the machine, was there a significant difference between anaesthetics S and Q?

Doctors investigated two ways of measuring the effect of general anaesthetics. In one method they timed how long it took to stop blinking, and then repeated the investigation using a machine to record when brain activity showed they were unconscious. Blinking involves cholinergic synapses. Anaesthetic S is a similar shape to acetylcholine. Suggest how anaesthetic S stops the transmission across the synapse.

What reduces the concentration of neurotransmitter in a synapse after it has diffused across?

Using the diagram, name D

Using the diagram, name E

Why is the speed of conduction faster on myelinated neurones?

True or False: A stronger stimulus will generate more frequent action potentials.

Put the above events ( A-F) in order for the passage an action potential.

What do we call the process happening at '3' on the above diagram?

The plasma membrane of a neurone at rest is most permeable to which ions via facilitated diffusion?

What piece of equipment do animal scientists use to investigate the effect of different stimuli on invertebrates?

True or false : Kinesis is a random movement

What does this experiment by Went show?

What does Boysen and Jensen's experiment using agar show?

How does IAA bring about this effect?

What response do roots have to light?

Denitrifying bacteria use nitrates in the soil to carry out respiration and produce nitrogen gas. Are the vast majority aerobic or anaerobic?

Which process can occur due to the actions of Nitrosomonas bacteria?

What does GPP stand for?

The diagram above shows one form of anaerobic respiration, name molecule 'Y'.

In the absence of oxygen as the final electron acceptor, some processes of aerobic respiration cannot occur. Some of the processes however can continue, which is the last stage that can still function?

Is the column for Krebs in the above diagram correct?

How many molecules of ATP are generated by oxidative phosphorylation in the ETC from one molecule of glucose?

The ETC develops a proton gradient as the electrons pass through. What is the process of these protons moving down an electrochemical gradient called?

How many times does the Krebs cycle happen per glucose molecule?

How many carbon atoms does molecule X contain?

Glycolysis usually shows the breakdown of glucose, but is glucose the only respiratory substrate which can feed into glycolysis?

True or False - Using a different solvent does not alter the distance travelled by different substances in this technique?

In the above experiment, chloroplasts were isolated from plants grown at different light intensities. The mutant plants produced more chlorophyll b . The scientists predicted the mutant plants would grow better in any light intensity; why might this be?

Which substance is represented by I?

How many atoms of carbon in ONE molecule of substance C?

Name molecule F

How many carbon atoms are there in substance A?

Where in a chloroplast do the Light Independent Reactions ( LIRs) occur? ( watch your spelling!)

What is structure D?

Which membrane is represented by 'C' on the diagram?

The mRNA travels to the ribosome, where it feeds between the two subunits, exposing the template bases. tRNA molecules each carry a specific amino acid at the top, with a complementary sequence of three bases called an anti-codon at the bottom. The tRNA anticodons then complementary base pair with the mRNA codon.

In the ribosome there are 3 binding sites for tRNA, two where a peptide bond is formed between the carried amino acids. These amino acids then form a polypeptide chain which leaves the ribosome. The third site is a departure site, where the tRNA which has released its amino acid departs to pick up a new amino acid. Once the entire mRNA sequence has been ____11____, it can either pass into another ribosome to make another polypeptide or be degraded.

The mRNA travels to the ribosome, where it feeds between the two subunits, exposing the template bases. tRNA molecules each carry a specific amino acid at the top, with a complementary sequence of three bases called an anti-codon at the bottom. The tRNA anticodons then complementary base pair with the mRNA codon. In the ribosome there are 3 binding sites for tRNA, two where a peptide bond is formed between the carried amino acids.

These amino acids then form a ____10_____ chain which leaves the ribosome. The third site is a departure site, where the tRNA which has released its amino acid departs to pick up a new amino acid. Once the entire mRNA sequence has been ____11____, it can either pass into another ribosome to make another polypeptide or be degraded.

If hypermethylation happens to a tumour suppressor gene, what effect will this have on the rate of mitosis?

Cancer is often caused by a mutation causing a cell to divide uncontrollably and spread into other tissues. Name the gene that normally slows or reduces cell division:

How many samples should you take to get reliable data?

Speciation is when a new species arises from another: they can no longer produce fertile offspring because their DNA is no longer compatible. What term describes this inability between two populations to reproduce successfully?

The Hardy Weinberg principle only applies to a population that is or has ____.

Which Chromosome contains more genes?

Which of the above diagrams represents the myofilaments a 'Z line' in muscle?

The period of time after an action potential, when another action potential cannot pass along that section of a neurone is called the ____________ period ( Watch your spelling).

Mica is like thin glass, and is impermeable to most substances. What does Boysen Jensen's experiment inserting mica show ?

What does this experiment by Went show?

How does IAA become unevenly distributed?

The above diagram shows the phosphorus cycle. Name process B

Anaerobic respiration allows the regeneration of NAD+ in all organisms, which allows glycolysis to continue. How many ATP's are gained during anaerobic respiration of one glucose molecule?

Why did the student set up tube 1?

If 'X' on graph A represents 'Light Intensity', what effect would increasing carbon dioxide have on the line (represented in green on the diagram)?

In the above experiment, chloroplasts were isolated from plants grown at different light intensities. Why did the scientists measure the rate of oxygen produced?

Which two products from the Light Dependent Reactions ( LDRs) does the Calvin Cycle use?

Which membrane is represented by 'C' on the diagram?

Acetylation is the addition of a C2H3O group which contains a double bonded oxygen. Where does acetylation occur?

In humans, the zygote ( fertilised egg ) divides into a ball of cells called a Morula. What word describes the cells contained in a morula?

Which of the following would have the most dramatic effect on the primary structure of the polypeptide produced?

What word describes when a mutation causes all the following triplet codes to be misread in a different frame?

What is the biological meaning of succession?

What is the word used to describe 'All the different populations in a habitat along with all the abiotic conditions'?

What does 'p' represent ?

In the actual ratio of 6:1:1:6, there were more of the ginger and black eyed hamsters and more of the white with red eyed hamsters than expected. Therefore, there are proportionately fewer of the mixed traits (Ginger and red eyes and white with black eyes). What process allowed those few mixed trait offspring to occur?

Marfan Syndrome ( TGF Beta) is dominant (T) to the healthy recessive allele(t) . Having a V shaped hairline (V) is dominant to having a straight hairline (v). What percentage of the offspring of a father = TtVv and a mother TtVv will have Marfan syndrome and a V shaped hair-line ?

The muscle filament in the above diagram is relaxed, what would happen to the following zones when it contracts?

What type of sodium channels are opened when a Pacinian corpuscle is stimulated?

After an action potential has fired, the refractory period acts as the following:

• a) Prevents action potentials overlapping
• b) Limit the frequency of action potentials
• c) Limit the size of action potentials
• d) Makes action potentials travel unidirectionally.

After a stimulation has occurred, why do ions move out of an axon?

Across a resting human neurone plasma membrane, what is the average potential difference?

What does Boysen and Jensen's experiment using agar show?

True or False : Symbiotic fungi generally increase the amount of glucose in a plant.

How many carbon atoms are carried into the Krebs cycle in each Acetyl Co A?

Why did the student set up tube 1?

If 'X' on graph A represents 'Light Intensity', what effect would increasing carbon dioxide have on the line (represented in green on the diagram)?

Which two products from the Light Dependent Reactions ( LDRs) does the Calvin Cycle use?

True or False : Symbiotic fungi generally increase the amount of glucose in a plant.

This diagram shows part of the nitrogen cycle. Which two processes form nitrification?

The diagram shows an Arctic food web. Why is the energy efficiency between Forbs and Rock Ptarmigan lower than that between a Rock Ptarmigan and an Arctic Fox?

a) Because more of the body of the Ptarmigan is eaten than the Frobs.

b) Because more of the Ptarmigan is digested and absorbed (assimilated)

c) Because a Ptarmigan is bigger than a Forbs

If N = Net productivity, F = Energy in food, U = Energy lost in Faeces and Urine, R = Energy lost in Respiration. What would be the formula for Net productivity?

What does GPP stand for?

The diagram above represents anaerobic respiration in which type of organism?

If oxygen isn't available, which substance cannot be regenerated in high enough amounts to keep the system running?

Is the column for the ETC reaction in the above diagram correct?

How many molecules of reduced NAD ( or NADH) are generated in aerobic respiration from one molecule of glucose?

Isocitrate dehydrogenase is an enzyme used in the Krebs cycle to convert Citrate into the 5C intermediate. IDH1 is an inhibitor of Isocitrate dehydrogenase. What would happen to the concentration of Oxaloacetate produced by cells exposed to IDH1 ?

How many carbon atoms are in a single molecule of Oxaloacetate?

What happens to molecule C?

How many carbon atoms does molecule X contain?

How many phosphate groups are present in hexose bisphosphate?

How do you calculate the Rf value for a substance?

How many molecules of ATP are required to generate TWO molecules of glucose ?

Name substance C

What does substance H do to substance B?

How many carbon atoms are there in substance A?

In the chloroplast, many chlorophyll molecules (and other pigments) are attached to protein complexes in the internal membranes, labelled 'A' on the diagram. What are these complexes called ? ( Plural please!)

Which of the above diagrams represents either end of an 'A Band' in muscle?

In the above image, which type of protein makes up the myofilaments labelled C? type your answer in carefully.

When the layers of connective tissue are pressed, what happens to the neurone membrane?

Name part B on the above diagram (type your answer).

On the diagram, F is a voltage gated ion channel on an excitatory synapse, but which type of ion does it allow through?

Using the diagram, name C

Why does an increase in temperature ( up to 40 degrees) cause an increase in the speed of conduction along a neurone?

Many peripheral neurones (including motor neurones)have cells wrapped around the axon.

What are these cells called? ( type your answer- watch your spelling).

True or False: A stronger stimulus will generate more frequent action potentials.

What do we call the process happening at '3' on the above diagram?

In the above experiment, you hypothesised that a woodlouse responds by kinesis to a change in light intensity. What would be the best way to measure a response which shows kinesis?

In the above experiment on woodlice, what is the Independent variable?

Honey bees can detect the polarised light from the sun and use it to navigate even in cloudy weather. Is this taxis or kinesis?

Blow fly maggots have a light sensitive spot on their head, which they use to move away from light. Is this taxis or kinesis?

What would be a suitable control for Went's experiment ?

Which of these statements about Went's experiment is NOT true?

What does Boysen and Jensen's experiment using agar show?

What does Darwin's experiment where he removed a shoot tip then replaced it show?

In root tips growing parallel to the soil, where will the highest concentration of IAA be found ?

Which of the following is an example of a plant growth factor?

Between stages B and C, what will happen to soil depth?

What do we call a stage of succession?

You can also use a transect to sample a population. When should a transect be used?

Which of the following is an abiotic factor which effects population size?

Which of the following isn't an example of genetic drift?

Natural selection can change allele frequencies over time, due to those with the best alleles surviving and reproducing. What is the term used to describe the 'chance' or 'random' selection of alleles in a population?

An alteration in bird calls caused by difference in beak size, preventing mating calls between individuals of the same population is an example of what type of speciation?

What type of variation is show in the graph?

Which type of selection is shown by Darwins finches, where small and large beaks were both at an advantage due to different food sources?

Natural Selection is when organisms which are better adapted are more likely to survive and pass on their genes. Factors which affect the chance of survival are called selection pressures. These can be positive ( advantageous) or negative ( disadvantageous). Which of these is a negative selection pressure?

Tay Sachs is a recessive disease which leads to the build up of certain lipids which eventually become toxic. The Cajun community in the USA has an incidence of about 1 in every 3,500 births. What is the number of sufferers of Tay Sachs in a Cajun population of 100,000 people?

In peppered moths, having light coloured wings is dominant. In Sheffield (an industrial northern town in the UK) a sample of moths was taken. The numbers collected were 73 light coloured , and 326 dark coloured. What is the allele frequency ( as a decimal) of the light allele in the population?

What is the definition of a species?

This gene interaction once again alters the phenotype ratio. Which type of Epistatic allele will produce a ratio of 9:3:4?

In hamsters two genes are autosomally linked : Fur and Eye colour . Where Ginger fur = G, and White fur =g. Black eyes = B and red eyes = b. In a cross between a homozygous recessive male for both traits and a heterozygous female for both traits , what would be the expected ratio of Ginger & Black eye, White and Black eye, ginger and red eye and white with red eyes?

Which chromosome carries the sex linked alleles?

How can you tell when an allele is recessive in a pedigree (a family tree)?

What is the definition of 'heterozygous'?

What is the definition of 'phenotype'?

PCR allows DNA to replicate by semi-conservative replication. But what word best describes the rate at which it amplifies?

In a PCR reaction, the DNA is heated at the start of the cycle to around 95 degrees C. What is the reason for this?

Sometimes, two marker genes are used: The first marker gene is often an antibiotic resistance gene to show if the plasmid is present; the bacteria can only grow on a plate containing the antibiotic, if they have the antibiotic resistance gene on the plasmid. The second is often a gene with a colour change, which is broken by the insertion of the fragment.

e.g. An example of a gene to test for the presence of a fragment is Green Fluorescent Protein (GFP) glowing or not. What would a bacterial plate look like that contained an antibiotic, and was spread with bacteria which had been transformed with a plasmid and had a new gene fragment in?

If a bacterium contains a recombinant plasmid, then it will express the new 'foreign' gene as well as it's own. Which of the following is not a product made by recombinant bacteria?

What effect will increased acetylation have on a gene?

Which area of DNA is particularly affected by methylation?

Cell differentiation is the process of stem cells becoming more specialised into different types of cell. e.g. Muscle, bone etc. But what is the cause of this differentiation?

What does the 'si' stand for in siRNA?

Which level of protein structure will the binding of oestrogen alter?

What is the oestrogen receptor called when the oestrogen has bound?

Where is the oestrogen receptor located?

Oestrogen can act as a transcription factor. To do so, it needs to bind to what molecule?

Where are transcription factors often stored?

What is the difference between mRNA and pre-mRNA?

Which molecule is created during transcription?

Fill in the missing word : Causes of Mutations A mutation is any change to the order of __12___ in the genetic code. These occur naturally as the enzyme _____13_____ replicates the DNA and makes mistakes.

The incidence can also be produced due to exposure to certain agents called mutagenic agents. These can be chemicals such as nitrous acid, which converts cytosine to uracil. Nitrous acid would therefore cause a __14___ mutation. Ethidium Bromide is used to stain DNA during gel electrophoresis. It can insert between bases, acting in a similar way to an addition mutation and therefore causing a __15___ along the rest of the gene.

UV radiation is also a mutagenic agent. It can cause bonds to form between pyrimidine bases ( thymine and cytosine). This bonding causes polymerases to misread or stop working all together at that point.

What type of mutation causes a sequence of bases to be reversed?

Which word describes the sequence of three bases on DNA that code for an amino acid?

Each complementary strand of DNA runs in opposite directions. What word describes this?

Name the type of bond which forms the backbone of the DNA strand.

Tristan De Cunha is an island populated by a small number of Britons in the early 1800's. What is this an example of ?

During Metaphase 1, the homologous pairs can line up with either the paternal chromosome above, or the maternal chromosome above. What is this phenomenon called?

What do H and h represent?

Which type of DNA is not circular?

How do you calculate the rate of water transpired by the plant?

Which chamber do you think the green line represents?

Name the structures labelled A

Where in a human, is the affinity of haemoglobin for oxygen the highest?

What is the correct term for the cells which make up the alveolar wall?

True or False - Plasma cells are clones.

Which of the following is a similarity between diffusion an osmosis?

In the above diagram, there are three membrane proteins: A, B and C. Which represents where facilitated diffusion occurs?

Which of the following factors when increased, will decrease the rate of diffusion?

a) The Concentration Gradient

b) The Surface Area

c) The Diffusion Pathway

What name describes the double layered structure of a membrane? (Spell it correctly)

Which part is hydrophilic?

Why must the solution used to homogenise be cold?

Which of the following are NOT visible with a light microscope?

a) Plant Permanent Vacuole
b) Rough Endoplasmic Reticulum
c) Golgi Body

What type of bond forms between water molecules?

On the above diagram, which letter represents the product?

What does R stand for on an amino acid?

What is the name of molecule B?

In this experiment bacteria grown in N¹⁵, were then treansfered to N¹⁴, and allowed to divide for two generations ( tubeB). Describe what the cenrifuged DNA bands would look like.

Which direction does the enzyme move along the template strand A?

Which enzyme breaks the bonds between complementary base pairs in preparation for DNA replication?

How many bonds form between a 'C' and a 'G' ?

Will increasing the concentration of substrate cause an increase in the rate of an enzyme inhibited by a non-competitive inhibitor?

Which line shows the rate when substrate is limited ?

Why does the graph plateau?

Which letter on the above graph shows when the enzyme is denatured?

A scientist measured the rate of removal of amino acids from a polypeptide with and without an enzyme present. With the enzyme present, 500 amino acids were released per second. Without the enzyme, 2.0 × 10^-8 amino acids were released per second. Calculate by how many times the rate of reaction is greater with the enzyme present.

What is the function of the active site?

a) To hold the substrate in such a way as to strain the bonds so they are easier to break. or
b) To hold the substrate in such a way, as to allow new bonds to form.

True or False : Endothermic enzyme controlled reactions do not require activation energy?

What is the name of the COOH group on an amino acid molecule?

Which best represents the hydrophobic area on this diagram?

Which of the above three molecules shows a correct bond between glycerol and a fatty acid?

What type of bond joins a fatty acid to a glycerol molecule?

Which monomer is the animal storage polysaccharide made out of ?

Which monomer is this polysaccharide made out of?

How do you convert sucrose (which will test negative for a reducing sugar) , into monosaccharides which will test positive as a reducing sugar?

What type of reaction is used to join two monosaccharides?

Read the above passage. Before reweighing, the potato was blotted dry. Which of the following is NOT a reason for doing this?

A worm native to fresh water will die when placed in sea water. Why is this?