Class notes
FIRST CLASS Lecture notes Genetics
- Course
- Institution
Transmission genetics lecture notes
[Show more]
Seller
Follow
jessicabrown-11
Content preview
Transmission genetics 1: cell and organismic reproductionImportant message:
In both prokaryotes and eukaryotes cell division has no
effects on allele frequencies. In eukaryotes meiosis
(making haploid cells) is also a “fair” process: half the
gametes of an Aa heterozygote are A and half are a.
These 2 insights are key to transmission & population
genetics.
1.1 prokaryotic and eukaryotic cells differ in a number of
genetic characteristics
Prokaryotes:
Unicellular (mostly), with no compartmentalised cell
structure
Prokaryotic DNA does not exist in the highly ordered and
packaged arrangement (but can have some structure e.g.
supercoiling)
Made up of eubacteria and archaea
Eukaryotes:
Both unicellular and multicellular with compartmentalised
cell structure
Its genetic material is surrounded in a nuclear envelope to
form a nucleus
DNA is closely associated with histones to form tightly
packed chromosomes (couldn’t get all that DNA in our
cells without packing. Sperm use protamines rather than
histones to ensure even tighter packing)
Eubacteria cell replication:
Simple division: separation of replicated circular
chromosome
Single Origin of replication (not true in archea) – in many
species genes commonly co-orient with the direction of
replication to prevent DNA polymerase (for replication)
and RNA polymerase (for transcription) clashing head on
, High rate of replication – in some species, genes near the
origin of replication are the most highly expressed as they
are diploid more often
Genes with related functions tend to cluster (both in and
out of operons) and be co-expressed
Eukaryotic cell replication: chromosomes:
In a diploid cell, chromosomes form a homologous pair
(humans have 23 pairs of chromosomes)
The chromosomes have specialist anatomy to enable cell
division:
- Centromere: attachment point for spindle microtubules.
Tend often to be gene poor domains.
- Telomeres: tips of a linear chromosome – need to be
stabilised to stop them falling apart
- Origins of replication: where DNA synthesis begins. There
are multiple on every chromosome.
The cell cycle is tightly coordinated with key check points
1.2 they face the same problem: cell reproduction requires
the copying of the genetic material, separation of the
copies, and cell division
The Cell Cycle:
Interphase: an extended period between cell divisions,
DNA synthesis, and chromosome replication phase
M phase (mitotic phase): two different parts:
- Mitosis: separation of sister chromatids
- Cytokinesis: separation of cytoplasm
Phase check points: key transition/ quality control
points
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 jessicabrown-11. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.74. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75323 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now