Genetics - Ch. 8

Contains complex info, replicate faithfully, encode the phenotype, have the capacity to vary.

4 general characteristics genetic material must posses.

Transforming principle

DNA

How did they show that DNA is passed to new phages in phage reproduction?

Isotopes of phosphorus & Sulfur

Sugar, phosphate group, nitrogen containing base

Three parts of a DNA Nucleotide

RNA vs DNA

RNA has a hydroxyl group (OH), is single stranded, U instead of T, and not chemically very stable. DNA only has a hydrogen atom (H)

What are some of the important genetic implications of the DNA structure

10 base pairs/turn, Right handed helix, double stranded, major groove & minor groove, sugar/phosphate backbone, antiparallel strands

Replication, Transcription, Translation

3 major pathways of information flow within the cell

Positive supercoiling

Over-rotated molecules

Negative Supercoiling

under-rotated molecules

What is supercoiling

Partial solution to cells DNA packing problem

Euchromatin

The normal process of condensation and decondensation in cell cycle

Heterochromatin

Highly condensed state throughout the cell cycle

Nucleosome

A core particle consisting of DNA wrapped about 2 times around 8 histone proteins

Epigenetic’s

Changes in phenotype without mutation, passed on to future generations

Telomere

Natural ends of a chromosome, caps that stabilize the ends of chromosome and provide a means of replicating the ends of a chromosome

Bacterial Chromosomes

DNA does not exist in open relaxed circle

Eukaryotic Chromosomes

single, long linear molecule of DNA that is tightly packed

Topoisomerase

Enzyme responsible for cutting DNA to relieve tension & hold supercoiling steady

Scaffold Proteins

Proteins that organize the loops

Prokaryotic Chromosomes

1 circular double helix

Eukaryotic Chromosomes

1 linear double helix

Centromere

Constricted region of a chromosome where spindle fibers attach.