practice exam questions thread

[Stevensmay]

http://www.vcaa.vic.edu.au/Documents/exams/biology/bioassessrptnov06.pdf

Q1.d)
It states that "the mice with grey coats were known to be homozygous" in the first paragraph.
The genotypic ratio is: 1/4 YY, 1/2 Yy, 1/4 yy.
Wouldn't that mean a phenotypic ratio is: 2 yellow, 2 grey?

I know YY couldn't be grey, but it does say "the mice with grey coats were known to be homozygous".

All the mice with grey coats are homozygous, just some are homozygous dominant and some homozygous recessive.

Homozygous dominant = yellow
Homozygous recessive = grey

[Snorlax]

Got some questions
A person will gain long-term immunity after:
A) Administration of the rubella vaccine
B) An injection of iG if exposed to mumps
C) The inflammatory response to a wasp sting
D) The passage of antibodies from their mother.

Now i chose A, but apparently it's C.

Also, another question
A polypeptide found in the cytoplam of a cell contains 30 amino acids. How many nucleotides would be required in the mRNA for this polypeptide to be translated?
A) 23.
B) 60
C) 90
D) 93

Answer was D, but I chose C. Does the start OR stop codon NOT code for an amino acid?


Another Q:
An anticodon has the sequence CUA. The original sequence of DNA would be:
A) GUA
B) GTA
C) CAU
D) CTA

I answered it D, but answers say it's B.
If an anticodon has the seq. CUA, the mRNA has the sequence GAU, and so the DNA strand will have CTA?

PS. All these are from chemology 2013.
Thanks!
Need this last minute revision stuff out of the wayyy

[Irving4Prez]

Got some questions
A person will gain long-term immunity after:
A) Administration of the rubella vaccine
B) An injection of iG if exposed to mumps
C) The inflammatory response to a wasp sting
D) The passage of antibodies from their mother.

Now i chose A, but apparently it's C.

Also, another question
A polypeptide found in the cytoplam of a cell contains 30 amino acids. How many nucleotides would be required in the mRNA for this polypeptide to be translated?
A) 23.
B) 60
C) 90
D) 93

Answer was D, but I chose A. Does the start OR stop codon NOT code for an amino acid?


Another Q:
An anticodon has the sequence CUA. The original sequence of DNA would be:
A) GUA
B) GTA
C) CAU
D) CTA

I answered it D, but answers say it's B.
If an anticodon has the seq. CUA, the mRNA has the sequence GAU, and so the DNA strand will have CTA?

PS. All these are from chemology 2013.
Thanks!
Need this last minute revision stuff out of the wayyy

I would say the same for the first question.

As it asks for "nucleotides" you'd simply mutiple 30 by 3 and add 3 as the stop codon isn't an amino acid. AUG however, codes for methionine which IS an amino acid.

I would have gone with D as well.

[Snorlax]

LOL crap. for the polypeptide one I meant 90!
I got C, but answer was D.

So, the start codon codes for an amino acid, but a stop codon doesn't?

[Irving4Prez]

LOL crap. for the polypeptide one I meant 90!
I got C, but answer was D.

So, the start codon codes for an amino acid, but a stop codon doesn't?

Haha, yes.

[Irving4Prez]

Are inter neurons a part of the reflex  arc?

[Snorlax]

Are inter neurons a part of the reflex  arc?

yeah they are. Interneurons/connector neurons are what connects neurons within the CNS.
Reflex arc is just a pathway involved in a reflex action, so nothing's different. sensory>inter>motor

[ctoom14]

related question 15 (MC) from 2010 exam 2

not the exact question but is  a male that is
XA Y
homozygous normal?
if not what do we call it?

[Irving4Prez]

related question 15 (MC) from 2010 exam 2

not the exact question but is  a male that is
XA Y
homozygous normal?
if not what do we call it?

Non affected male OR normal male. I wouldn't include the 'homozygous' part

[ctoom14]

Non affected male OR normal male. I wouldn't include the 'homozygous' part

yeah fair enough, thanks

[lolipopper]

whats the difference b/w selective agent and pressure?

[Scooby]

Are inter neurons a part of the reflex  arc?

Sometimes. In a monosynaptic reflex arc you'll just have a sensory neuron that synapses with a motor neuron. In a polysynaptic reflex arc there'll be an interneuron between them

[TrebleClef]

I think a selective agent is an environmental factor that acts on the different phenotypes in a population, and this becomes a selection pressure, then natural selection occurs.

[Scooby]

whats the difference b/w selective agent and pressure?

You can pretty much use them interchangeably. The selection pressure is the effect that the selecting agent exerts on the population. The selecting agent is whatever is conferring a selective advantage or disadvantage to a particular phenotype

You could write something like "a selecting agent is introduced to the population" or "a selection pressure is applied to the population"

[lolipopper]

Thanks

I think a selective agent is an environmental factor that acts on the different phenotypes in a population, and this becomes a selection pressure, then natural selection occurs.

also are B cells part of humoral immunity? Lisachem 2006 says they aren't only antibodies are.