CELS 191 Lecture 10

structure of DNA ( the main features of the Waston-Crick model of DNA) [1]

DNA has a double stranded helical structure

structure of DNA ( the main features of the Waston-Crick model of DNA)[2]

the sugar phosphate backbone is on the outside

structure of DNA ( the main features of the Waston-Crick model of DNA)[3]

the bases on the inside

structure of DNA ( the main features of the Waston-Crick model of DNA)[4]

Stabilised by hydrogen bond

structure of DNA ( the main features of the Waston-Crick model of DNA)[5]

the two polynucleotide strands are oriented in opposite direction

orient

quay về phía

stabilised

làm ổn định

Components in DNA [1]

phosphate group

Components in DNA [2]

sugar ( deoxyribose sugar0 5 carbon sugar

Components in DNA [2]

Nitrogenous base- A,T, G,C

formation of a polynucleotide [1]

Nucleotide monomers are joined together with phosphodiester group bounds to form a polynucleotide( nucleic acid[deoxyribonucleic acid for DNA)

what is polynucleotide?

is simplify a long chain of nucleotides.

what does the DNA consist?

two polynucleotide strands twisted into a double helix

twist (v)

xoắn

helix

xoắn ốc

formation of the phosphodiester bond

the hydroxyl group (OH) on the 3rd carbon of one nucleotide reacts with the phosphate group attached to the 5th carbon on another nucleotide

nucleotides in polynucleotide chai are connected by

Phosphodiester bond

each DNA strands has direction

5’→3’,3’ <- 5’( antiparallel orientation)

Geometry

hình học

DNA form

a double helix

two polynucleotide strands

coil around each other

coil

twist

sugar phosphate backbone

on the outside

base point

inward

helical structure provides

stability

Base pairing model

A pairing with T → 2 hydrogen bond

model

kiểu hình, mẫu

base pairing model

C pairing with G → 3 hydrogen bonds

Base paring model (1st role)

Ensures accurate DNA replication

Base paring model (2nd role)

Maintain constant width of the helix

Base paring model (3rd role)

hold strands together but allow them to seperate when needed

accurate(adj)

đúng đắn

constant

không đổi, bất biến

width(n)

bề ngang, rộng

Semiconservative DNA replication

is the way of DNA copies its self before self division

replication

sự tái tạo

New DNA contains [1]

one original parent strands

New DNA contains [2]

one newly synthesised strand

How does the DNA replication work?[1]

DNA unwinds and unzip ( the double helix seperates into two strands)

How does the DNA replication work?[2]

Each strands acts as a template ( New nucleotides pair will exposed bases (A-T,C-G)

How does the DNA replication work?[3]

New strands are built( Enzymes join nucleotides together, forming new polynucleotide chains)

How does the DNA replication work?[result]

two indentical molecule( 1old strand, 1 new strand)