Lets get some help with Biology!

C'mon You know you want to... :smile:

I know there are some people here who are just esk at Bio, and I need some help becuase ive got an exam tomorrow and im SCREWED becuase I dont know anything, but there is a good side, usually id be really really screwed but tomorrow's exam is a knowledge paper which means I can cram for it... heres a few questions... and I will award as much rep as I can!

and yes, to you guys these questions will seem pitiful, but I will be the first to admit that Bio has never been my strong point and never will be, but im pointing out things from my study I dont know.
mostly DNA related stuff..

1) Define> Histone and Centromere
2) What exactly is a gnome
3) What are the defferences between female and male karyotypes for HUman Beings?
5) What are the elements of a neucleotide?
6) What is the purpose of transcription?
7) and translation?
8) What roles do enzymes play in the process of transcription and replication?
9) What is a mutagen?
10)Give a definition of Homeostasis

Thankyou!~!! I love you!!! please save my life!!!! :redface:

Reply 1

MalaysianDude

Everdawn

C'mon You know you want to... :smile:

1)Histone = Organelles which allows DNA to coil around it reduce the area needed to store genetic material
Centromere = Organelles which holds the sister chromatids together during cell division

2)Genome = Total genetic material in a cell or individual

3)Female has XX as the sex chromosomes and males has Xy as the sex chromosomes

5)A molecule comprising either a purine or pyrimidine base bonded together with a phophorylated ribose

6)To produce mRNA

7)To form peptide bonds which codes for the sequence between amino acids

8)Enzymes mostly are transferase enzymes which transfers materials from one point to another

9)A substance which induces mutation

10)The regulation of a constant internal enviroment when external conditions begin to fluctuate i.e. -ve feedback and +ve feedback

Reply 2

Everdawn

thanks man, rep coming your way.

Reply 3

Elles

i think this is probably too late..but thought i'd see how much my revision the other day went in!

1) Define> Histone and Centromere

Histones = for DNA packaging. structure of DNA is such that is strong acid - would be damaging in cells plus huge length ~2m, so has to be packaged into chromatin, which compressed & neutralises charges & histone proteins to do this. highly conserved between species h1 h2 h2a h4 (?). coils up into solenoids w/ H1. major & minor grooves still exposed, Zn fingers & euchromatin/heterchromatin dependent on function.

Centromere = joins two sister chromatids. can be metacentric, sub centric or acrocentric. kinetochore attaches to in metaphase. 'junk' DNA/repeating sequences make up.

2) What exactly is a gnome

Genome..erm..all the DNA of an organism? not sure if it includes junk, i suppose so.

3) What are the defferences between female and male karyotypes for HUman Beings?
22 autosome pairs & a sex chromosome pair.
genotypic maleness arises from Y chromosome or an SRY translocation (key gene on Y)
general XX = female & XY = male
Turner's = XO (female) Klienfelter's = XXY (male), XYY (male)

5) What are the elements of a neucleotide?

nucleoside = ribose sugar & phosphate group. + a base = nucleotide. in DNA: A&G are purine bases TC = pyrimidines.

6) What is the purpose of transcription?

DNA --> mRNA, so genetic info can leave nucleus (assuming we're talking about prokaryotes)
also allows post transcriptional modification of mRNA - exon shuffling, targetting.

7) and translation?

mRNA --> protein.. would all be futile otherwise!

8) What roles do enzymes play in the process of transcription and replication?

pff..quite an important one. Pol I - rRNA Pol II - mRNA & PolIII-tRNA> exonuclease for 3' -5' proofreading

replication - helicase & topoisomerase to unravel & keep unwound. & polymerase to join.

9) What is a mutagen?

substance that causes mutation? damage DNA, UV light, carcinogenes, activated oncogenes. teratogens = cause embryonic mutation - trauma, chemicals etc.

10)Give a definition of Homeostasis

maintainance of the internal millieu of the body.

hmm..more revision needed i think.. :rolleyes:

Lets get some help with Biology!

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