Class notes

Class notes (BIOM2131) Intro molecular biology - Essential Cell Biology, 4th Edition

0 purchase

Course
BIOL (BIOM2131)

Institution
University Of Windsor (U Of W )

In depth chapter notes from the book Essential Cell Biology, 4th Edition. Covers materials for BIOM 2131 for professor Martin.

[Show more]

Preview 2 out of 12 pages

View example

Uploaded on July 22, 2023
Number of pages 12
Written in 2022/2023
Type Class notes
Professor(s) Martin
Contains All classes

biom2131
university of windsor
class notes

Institution
University of Windsor (U of W )
Education
Biomedical Sciences
Course
BIOL (BIOM2131)

$7.99

Add to cart

Save

100% satisfaction guarantee
Immediately available after payment
Both online and in PDF
No strings attached

Chapter 7

- DNA does not synthesize proteins by itself Portions of DNA sequence are transcribed into RNA
- Nucleotide sequence of the appropriate segment of DNA is copied
- The process of making RNA from gene (the functional segment of
to be transcribed to RNA
DNA) is called transcription because it is still written in the same
- The resulting RNA is translated into proteins
language of nucleotides (only a section of DNA, the gene is
- This is a fundamental principle, termed the central dogma which
transcribed, not the whole genome)
states that the flow of info is only in one direction, from DNA, to
- RNA is a linear polymer of 4 different nucleotide subunits (adenine,
RNA, to protein; or from RNA to protein
uracil, cytosine, and guanine)
- 2/3 of the genes are transcribed into protein
- RNA differs from DNA in 2 aspects:
- tRNA and rRNA are not translated into proteins
- The nucleotides are ribonucleotides because their sugar is ribose
- some RNA gets deleted immediately after translation
sugar
- In eukaryotes transcription takes place inside the nucleus and
- Instead of the base thymine, there is uracil, and it bonds in the same
translation takes place outside the nucleus
manner as A-T
- In prokaryote both take place at the same time in same region
- There are major differences in overall structures of DNA and RNA
- After translation, not all polypeptides are functional
- RNA is single stranded
- Even if they are functional and form an amino acid, they might be
- This allows RNA to fold into a variety of shapes
turned off
- The ability of RNA to fold into a complex 3D shape allows it to carry
From DNA to RNA out various functions such as structural, regulatory, and catalytic
roles
- Identical copies of many RNA can be transcribed from the same
- tRNA are about 80 nucleotides long
gene to make many of the same protein
- Allows cell to rapidly make large amounts of proteins
- Transcription and translation can take place at different rates to
allow cells to make vast amounts of some proteins and small
amounts of other
- DNA double helix is opened and only one of the strands is used as
the template
- The template strand is called the nonsense strand but the non
template strand is called the sense strand and the coding strand
- The nonsense/template strand is the one copied to be translated
into RNA
- Transcription happens from 5’ to 3’
- The ribonucleotides come as rNTPs and then are phosphorylated
- The RNA strand does not stay bound to the DNA template; the
strand instantly falls off as primase makes it

, Transcription produces RNA that is complementary to one strand of DNA Cells produces various types of RNA

- RNA is made by transcription - mRNA are the RNAs that direct the synthesis of proteins
- Transcription begins by unwinding a section of DNA to expose the - in eukaryotes, mRNA carry info from a single gene that codes for a
bases single protein
- One strand of the DNA acts as a template - in bacteria, more than one gene is used to transcribe a mRNA which
- Ribonucleotides are added in the same fashion as nucleotides, if it is therefore carries info for more than 1 protein
a good match, RNA polymerase covalently bonds the ribonucleotide - however, some final products of genes are RNA itself
to the DNA base - these RNAs are tRNA, rRNA, miRNA and other noncoding RNAs
- It is complimentary to the DNA template - they are responsible for several roles such as serving as regulatory,
- Unlike DNA daughter strands, RNA does not stay hydrogen bonded structural, and catalytic components of the cells
to the template strand - rRNAs form the structural and catalytic core of the ribosomes which
- As soon as the RNA is separated, DNA double helix binds again translate mRNAs into proteins
- Due to this and the fact that only one strand is used as a template, - tRNAs act as adaptors that select specific amino acids and hold
RNA is single stranded them in a place on a ribosome for their incorporation into protein
- RNA is also shorter because only a small section of DNA is - miRNA act as key regulators of eukaryotic gene expression
transcribed - gene expression refers to the process by which info in a DNA
- DNA molecules can be up to 250 million nucleotide pair long, but sequence is translated into a product that has some effect on a cell
RNA is no more than 1000 nucleotides long or organism
- RNA polymerase catalyzes the formation of the phosphodiester - gene expression includes both translation and transcription
bond and forms the sugar phosphate backbone of the RNA chain
signals in DNA tell RNA polymerase where to start and finish
- The polymerization takes place in 5’ to 3’ direction
transcription
- Ribonucleoside triphosphates provide the energy needed for the
reaction to take place - In bacteria, initiation of transcription takes place when RNA
- The immediate release of the RNA molecule allows many RNA to be polymerase collides with a DNA molecule and stick firmly to the
synthesized form the same gene in a very short time; synthesis can double helix and then slides rapidly along its length
begin before the other RNA is made - When it finally encounters a sequence region called the promoter, it
- it takes approx. 50 seconds for a 1500 nucleotide to be transcribed latches more tightly
- more than 1000 transcripts can be synthesized in an hour - Then the RNA polymerase unwinds the double helix to expose the
- RNA polymerase uses ribonucleoside for phosphates as substrates, base
so it does catalyzation of ribonucleotides - Two ribonucleoside triphosphates are joined together by
- RNA transcription can begin without a primer because it does not polymerase to begin synthesis of the RNA chain
need to be very accurate as it is not used as a permanent storage - Chain elongation takes place until polymerase encounters the
form of genetic info terminator
- RNA polymerase makes 1 mistake every 10^4 nucleotides - The terminator sequence is transcribed in the 3’ end of the RNA
transcribed chain polymerised; the terminator sequence is transcribed into the
RNA transcript too

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller zararasheed. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $7.99. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

66184 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 15 years now

Start selling