Biology Random Retrieval Y13

What effect will having a high methylation of a promoter sequence , have on expression of that gene?

A methyl group has the structure CH3. Methylation is the addition of a methyl group onto what?

Cardiomyocytes are an example of what type of stem cell?

Which of the following is a difference between prokaryotic and eukaryotic DNA?

Which type of plants are more likely to be the pioneer species in secondary succession?

What is the advantage of carrying out an interrupted belt transect compared to belt transect?

Is predation a biotic or abiotic factor that effects population size?

If B = black, W = white and BW = speckled feathers in hens. Two heterozygous speckled hens mated, what will the ratios be of offspring that are black : speckled : white?

In guinea pigs, Short hair (S) is dominant to long hair (s). In a monohybrid cross between a heterozygous mother, with a heterozygous father, what ratio of long hair to short hair will the offspring have ?

What is the structural adaptation which gives rods high sensitivity compared to rod cells?

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

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

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?

What effect do inhibitory synapses have on the post-synaptic membrane?

In the above diagram, which graph shows the correct effects of increasing a stimulus?

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

Name protein B in the above diagram.

In the above experiment, chloroplasts were isolated from plants grown at different light intensities. What is the saturation point of Normal plants grown in high light?

If six molecules of molecule C are produced, how many will be regenerated into substance A?

What does molecule 'H' represent?

The above diagram shows the phosphorus cycle. Name process B

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

True or False : Fungi can increase the uptake of water by a plant

External digestion involves the secretion of enzymes outside of the organisms outer-most layer. Which term best describes this?

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

In the formula for the calculation of NPP, what does the 'R' stand for?

What does GPP stand for?

In this investigation, are the yeast respiring anaerobically or aerobically ?

The diagram represents anaerobic respiration, name substance 'Z'.

Is the column for Krebs in the above diagram correct?

What term is used to describe the whole process of using energy from electrons in Redox reactions to generate ATP called?

As the ETC flows, what will happen to the pH of A?

What is the final electron acceptor of the ETC?

A single molecule of W is produced per turn of the Krebs cycle, and it carries hydrogen off to the ETC. What is it?

Which substance goes on to create other organic molecules?

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

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

Once light has hit structure D, and the electrons have left the chlorophyll, they can either be passed on to form F or follow path 'G'. What is path 'G'?

What type of molecule is represented by 'C'?

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

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

The image above shows a muscle fibre. Name organelle E

The image above shows a muscle fibre. Name organelle C

When a stimulus is detected by a receptor, it generates a potential difference across it's plasma membrane. What is the name of this potential difference?

Synaptic knobs contain mitochondria, which of the following is NOT a use of ATP in the presynaptic neurone?

What term is used to describe when more than one presynaptic neurone releases its neurotransmitter onto single post-synaptic neurone? ( Type your answer carefully)

If a neurotransmitter binds to the post synaptic membrane and causes potassium ion channels to open, would it be excitatory or inhibitory?

True or False - The speed of conduction along an unmyelinated neurone is around 5 m/s ( jogging pace).

Why is the speed of conduction faster on myelinated neurones?

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).

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

What has happened at stage 5?

What causes a change in the type of channels that are open at stage '4' ?

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

Name protein C in the above diagram.

The resting potential of a neurone is maintained in part, by the Sodium-potassium pump. But which of the following shows the correct movement of the ions?

Maggots follow a scent up a concentration gradient towards a food source. Is this taxis or kinesis?

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

What does Darwin's experiment where he placed a black cover over the tip show?

Which of the following is true?

What is the native climax community in the UK?

What is humus?

At which stage will abiotic factors be most hostile?

Which of the following is not an assumption that affects the accuracy of the Mark Release Recapture population estimate?

How many samples should you take to get reliable data?

Why is random sampling used?

Was the cold winter an example of an abiotic factor or a biotic one?

A mild winter and a warm spring meant that the population of robins (birds which feed on insects) increased. This was due to the above average biomass of insects, so more young robins survived. However the following winter was very cold so fewer insects were available in the spring, and the robin population decreased. Is the decrease in robin population, intraspecific competition or interspecific competition?

Is the following an 'Abiotic adaptation' or a 'Biotic Adaptation': The Warbler Finch has a short slender beak for catching insects whilst, flying. Where as the Large Ground Finch has a strong , deep beak for crushing seeds.

What type of variation is show in the graph?

Which type of selection is when the number of individuals with a particular characteristic, increase around an extreme or outlier value?

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?

What is 'crossing over'?

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

What would be the genotype for a man with colour-blindness (b)?

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 'homozygous'?

What is a gene?

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?

What enzyme is needed in a PCR reaction ?

PCR is an example of what type of DNA amplification?

What do we call enzymes that cut DNA at specific base sequences?

How would the cDNA base sequence of a gene differ to the normal genomic base sequence of a gene?

A methyl group has the structure CH3. Methylation is the addition of a methyl group onto what?

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

Where is the oestrogen receptor located?

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 _____7_____ at the bottom. The tRNA anticodons then complementary base pair with the mRNA ____8____.

In the ribosome there are 3 binding sites for tRNA, two where a ____9____ 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 difference between mRNA and pre-mRNA?

Which of the following would NOT increase your exposure to oestrogen?

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?

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

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

TTA = Leu TTG = Leu TTC = Phe TCA = Ser TAA = Stop Here is the original sequence : TTCTTGTTATCATAA. Here is a mutated sequence: TTCTTATTATCATAA.

What type of mutation has occurred ?

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

Which two molecules does DNA Polymerase join together?

What attracts new 'free' nucleotides to the exposed template strand during DNA replication?

What does the C stand for in the genetic code?