TSR&#x27;s Girls vs Boys Biology Challenge

Original post by Felix Felicis

Coming from a non-biologist so please excuse me if I'm a no0b. :colondollar:

DNA replication is important in an organism to ensure that every cell in the body following mitosis has a copy of said orgasm's DNA set which is imperative for the production of RNA and proteins which dictate biochemical reactions within the body.

Briefly explain how proteins can act as buffers and the importance of this to the human body.

That was perfectly fine :wink:

Proteins are made up from amino acids. Amino acids consist of an amine group, and a carboxylic acid group. This arrangement allows them to exist as zwitterions. The amine group can pick up a proton, and the carboxylic acid group can react with a base, thus acting as a pseudo buffer.
pH needs to be regulated for many different reasons. Body fluid too basic or too acidic can damage the tissues, enzymes that regulate metabolism in the body need specific pH ranges to work and the protein buffer system is part of the body's mechanism for controlling blood Hydrogen (H+) ion homeostasis. Both intracellular and extracellular proteins have negative charges and can serve as buffers for alterations in hydrogen ion concentration. However, because most proteins are inside cells, this primarily is an intracellular buffer system blah blah I’ll easily go off topic…

Example

Haemoglobin is a pretty epic intracellular buffer because of it's ability to bind with Hydrogen ions forming a weak acid and carbon dioxide. After oxygen is released in the peripheral tissues, haemoglobin binds with CO2 and H+ ions. As the blood reaches the lungs these actions reverse themselves. Haemoglobin binds with oxygen, releasing the CO2 and H+ ions. The H+ ions combine with bicarbonate (HCO3) ions to form carbonic acid (H2CO3). The H2CO3 breaks down to form water (H2O) and carbon dioxide (CO2) which are excreted via expiration through the lungs. Therefore respirations help maintain pH

Score 84 including Felicia's which she forgot to put in :tongue:

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We had a discussion about semantic satiation in ScotQuals so using that for inspiration I ask:
What causes Déjà vu? Sorry if it's off syllabus but it's cool....

(edited 10 years ago)

Reply 82

ash1011

10

Im not really sure how this thread works but ill just attempt to answer the question I haven't done biology since GCSE :/

Is it basically when eating or drinking something cold it touches the roof of the mouth causing the area to become colder so the blood vessels there dilate to warm the area. this then causes nerves there to send pain signals to the brian causing a short term headache.

I didn't quite understand the thread aswell, had to edit twice :tongue:

Answer is correct, your question?

(edited 10 years ago)

Reply 83

Original post by -Neuro-

(...) We had a discussion about semantic satiation in ScotQuals so using that for inspiration I ask:
What is Déjà vu? Sorry if it's off syllabus but it's cool....

Déja vú means to re-experience a certain thing which was happen before in the same way at the time at the same place. In other words: to experience the same situation again.

Score 86

Question: what means the adjectiv lytic? name an example!

Reply 84

Original post by Kallisto

Déja vú means to re-experience a certain thing which was happen before in the same way at the time at the same place. In other words: to experience the same situation again.

Score 86

Question: what means the adjectiv lytic? name an example!

Where you asking what the definition of the word lytic was? :redface:

Lytic basically means it produces lysis. Lysis is The disintegration or rupture of the cell membrane, resulting in the release of cell contents or the subsequent death of the cell.

An example of where lysis is the normal process of viral reproduction involving penetration of the cell membrane, nucleic acid synthesis, and lysis of the host cell.

(Score 84)

Why is infection of the brain rare?

(edited 10 years ago)

Reply 85

Original post by -Neuro-

(...) Is this what you meant? :s-smilie:

If it is I'll add a score and a question.

You have defined the word. And you have also mentioned the viral production what I want to read as answer. To be honest you have mentioned a little bit more than expected. Name the current score and ask your question. Good job!

Reply 86

Eloades11

OP

17

Original post by -Neuro-

Why is infection of the brain rare?

By infection I'm assuming pathogens. They would have to get into the blood stream (avoiding the WBC's and other host defenses), and then cross the blood brain barrier. Or navigate themselves into neuronal cells/spinal cord, and navigate their way to the brain from there. Both very unlikely events.

Score 86

What is the role of DNA ligase?

Reply 87

Original post by Eloades11

(...) What is the role of DNA ligase?

The DNA ligase links the strands of DNA, in other words: this enzyme complete the genetic information.

Score 88

What is the role of histones?

Reply 88

Original post by Kallisto

The DNA ligase links the strands of DNA, in other words: this enzyme complete the genetic information.

Score 88

What is the role of histones?

Histones are the proteins closely associated with DNA molecules. Histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are responsible for the structure of chromatin and play important roles in the regulation of gene expression.

(Score 86)

Explain why individuals can carry the HIV virus for many years and remain
symptom free.

Reply 89

Original post by -Neuro-

(...)

Explain why individuals can carry the HIV virus for many years and remain
symptom free.

I have an assumption: It is a temporary virus, that is to say the DNA of new viruses are remain in a cell. It is not a lytic virus which broke out when the DNA of new viruses was synthesized. That is why the genetic information remain in the cell, even if after cell divisions.

Is this answer acceptable? then it is my turn again!

Reply 90

Eloades11

OP

17

Original post by Kallisto

I have an assumption: It is a temporary virus, that is to say the DNA of new viruses are remain in a cell. It is not a lytic virus which broke out when the DNA of new viruses was synthesized. That is why the genetic information remain in the cell, even if after cell divisions.

Is this answer acceptable? then it is my turn again!

If you ask a question in the same post, it helps keep the thread going. Otherwise we're all sat here waiting for you to make a question :smile:

I don't think you should "temporary virus", it's more of the case that it reproduces slowly, and is not recognised by the immune system. It only targets CD4+ cells, so macrophages, T cells ect... The T cell count of an individual with HIV is lower than the average person.

Reply 91

Original post by Kallisto

I have an assumption: It is a temporary virus, that is to say the DNA of new viruses are remain in a cell. It is not a lytic virus which broke out when the DNA of new viruses was synthesized. That is why the genetic information remain in the cell, even if after cell divisions.

Is this answer acceptable? then it is my turn again!

What Eloades11 said and also that following infection by the HIV virus the viral RNA is reverse transcribed into DNA and a complementary DNA strand is synthesised. This double stranded DNA is integrated into the host genome where it can remain dormant for many years. The trigger that initiates synthesis of new viral particles is unknown.

Another question which I've decided to keep on a similar topic:

AIDS is characterised by susceptibility to a variety of diseases, including
pneumonia, tuberculosis and rare forms of cancer. Explain this.

Reply 92

Eloades11

OP

17

Original post by -Neuro-

What Eloades11 said and also that following infection by the HIV virus the viral RNA is reverse transcribed into DNA and a complementary DNA strand is synthesised. This double stranded DNA is integrated into the host genome where it can remain dormant for many years. The trigger that initiates synthesis of new viral particles is unknown.

Another question which I've decided to keep on a similar topic:

AIDS is characterised by susceptibility to a variety of diseases, including
pneumonia, tuberculosis and rare forms of cancer. Explain this.

Don't know why this was negged, it was a good response.

I do enjoy this topic, but I never covered it at A-level, can you make sure future questions can be answered by A-level students please :smile:

Basic terms: HIV weakens the immune system, allowing other infections which would otherwise be stopped by CD4+ cells, to prosper in the human body. Immune cells also destroy cancerous cells, so if the immune cells are weakened/dysfunctional/damaged then the cancer cells will keep multiplying.

Score 88. What is the function of a B-lymphocyte?

Reply 93

Original post by Eloades11

Don't know why this was negged, it was a good response.

I do enjoy this topic, but I never covered it at A-level, can you make sure future questions can be answered by A-level students please :smile:

Basic terms: HIV weakens the immune system, allowing other infections which would otherwise be stopped by CD4+ cells, to prosper in the human body. Immune cells also destroy cancerous cells, so if the immune cells are weakened/dysfunctional/damaged then the cancer cells will keep multiplying.

Score 88. What is the function of a B-lymphocyte?

I negged a subsciber on another thread and debated against her post in reply, her way of tackling it was to neg me back on any random post she could find :rolleyes:

Sorry

A type of lymphocyte that, when stimulated by a particular antigen, differentiates into plasma cells that synthesize the antibodies that circulate in the blood and react with the specific antigens. Antibodies are proteins that bind to specific antigens and mark them for destruction by, for example, marking them more recognizable to phagocytic cells. In this way, B lymphocytes "flag" cells for destruction by macrophages.

Would I be right in saying that B lymphocytes and antibodies respond primarily to bacteria and bacteria toxins in our body fluids?

(Score 86)

I'm not 100% sure if this is in A-level biology, it is in the Scottish Higher and it is one of my favourite topics :love:

When a normal strain of the Escherichia coli is placed in growth medium containing glucose, it undergoes rapid cell division. When the same strain of E. coli is placed in growth medium lacking glucose but containing lactose, there is a delay before cell division occurs. Account for these observations.

(edited 10 years ago)

Reply 94

Tillybop

18

Original post by -Neuro-

I negged a subsciber on another thread and debated against her post in reply, her way of tackling it was to neg me back on any random post she could find :rolleyes:

Sorry

A type of lymphocyte that, when stimulated by a particular antigen, differentiates into plasma cells that synthesize the antibodies that circulate in the blood and react with the specific antigens. Antibodies are proteins that bind to specific antigens and mark them for destruction by, for example, marking them more recognizable to phagocytic cells. In this way, B lymphocytes "flag" cells for destruction by macrophages.

Would I be right in saying that B lymphocytes and antibodies respond primarily to bacteria and bacteria toxins in our body fluids?

(Score 86)

I'm not 100% sure if this is in A-level biology, it is in the Scottish Higher and it is one of my favourite topics :love:

When a normal strain of the Escherichia coli is placed in growth medium containing glucose, it undergoes rapid cell division. When the same strain of E. coli is placed in growth medium lacking glucose but containing lactose, there is a delay before cell division occurs. Account for these observations.

Lactose is made up of the monosaccharides glucose and fructose. Therefore the E.coli have to break down the lactose into it it's monosaccharides using the enzyme lactase before it can use it. After this it divides.

Ooh and my question. Explain how the Sinoatrial and the atrioventricular nodes cause the heart to contract.

(edited 10 years ago)

Reply 95

Dynamo123

7

The SA node sends nerve impulses that cause the atria to contract. The AV node delays these nerve impulses so that the atria can empty into the ventricles.
Score 86 again :P

What is the supra-scapula?

Reply 96

Original post by Dynamo123

(...) What is the supra-scapula?

It is a bone above the back which belongs to the shoulder.

Score 88

What is peppered moth evolution and why it came into being?

Reply 97

ChrisE2

Original post by Kallisto

It is a bone above the back which belongs to the shoulder.

Score 88

What is peppered moth evolution and why it came into being?

The peppered moth had a black and white colouring to camouflage itself with the lichen of the trees, the moth evolved to a darker colouring due to the industrial revolution (many lichen died and trees became covered in soot so the moths were no longer camouflaged, and therefore adapted to protect against predation).

Score 90

Which species is the one previous to Homo Sapiens?

Reply 98