Summary Grade 12 IEB Life Sciences – DNA, Genetics & Meiosis Handwritten Notes

DNA STRUCTURE AND FUNCTION
-

Found in chromosomes inside the nucleus

of
eukaryoticalls
code Mitochondrial DNA
Contains the
genetic
-




- Double helix

-




DNA

At CG Inherit from mother
-
, -




only
-
extranuclear

-

Found in nucleus and cytoplasm
RNA
-
DNA replication
occurs in
Replaces interphase
Thymine
-
Semi-conservative


carries
code from
↓
genetic
DNA
↓
brings amino
a cids for
( one

one
old
new
strand
strand
to ribosome Protein
synthesis
-




Single-ringed Nitrogenous bases
-




Cytosine + Thymine Juracil in RNA)
I I
smaller PURE As Gold
-




-



Double-ringed Nitrogenous bases

-

Ademine + Guanine
larger
12 I 2 -




DT the Pyramids

Purines with
always pair pyrimidings T = A Double bond
>
-




keeps helix width consistent
. C = G Triple bond

, PROTEIN SYNTHESIS
O & ③

ReplicationNAtranscription NA translation PROTEIN
① Replication (Interphase before)
mitosis

1 . * DNA helicase causes weak
bonds between
hydrogen
to be
nitrogenous bases
broken

↓

. Free
2 nucleotides
floating in

complementary
·
nucleoplasm that are

to the original DNA strand ymers
to
attaches
complementary pair
↓
. Each original strand serves
3 as a
template : Semi conservative

Cone old , one new)
↓
4. New bonds form
hydrogen
↓
5
. molecule
helix
curls into
shape

6
. ↓
Two identical DNA molecules



·F new New