Summary Grade 12 Life Sciences - Cellular and Tissue Biology Guide

Liffe at a molecular and , cellular
Elsessme levell
T H E S T R U C T U R E o f DN A a n d R N A
The nucleic acds DNA and RNA are polymers of
estides
molecular structure made of three units
-complicated
.


phosphate
phosphate group baseermamide
&
=




&
e


Sugar
=




phosphate 7 baseme

=

nitrogenous base



ribonucleic and
I sugar I sugar
#
The four RNA bases




-
:
covalenton is
called :
phosphodiester bond
Adenine :
Kal :


O


N Il




-
One nucleotide bonds to
-




purine -



prymidine


I
·




#
Only RNA
-




in
another between the First

nucleotides the




·
and
sugar
phosphate of the next
Canine :g Cayosine :




nucleotide via a covalent
Il -



purina NHz
bond and this will take


H An-pyrimid
a
J




·
until we have a large

i
place

i polymer
nucleotides
- - - - - - -
with
many RNA

-




# deoxyribonucleic
add
Guanine is alway double bonded to cytosine All bases the except that
*
stay same

3' strand and thymine is
always triple bonded Instead of uracil that is
only found in
5'strand
& to Adenine :
RNA there is
&




swamust
G => C , A =
T mine HzC 9




I·
ant
--- this

a
is
complementary
purine always joins
base

to a
pairing as
pyramidine Y
be summer a

---
Antiparallel :




-je
double helix made of two 51
* DNA is a




a
antiparallel strands of nucleotides
Phosphodiester bond linkedby hydrogen bonding between
- -




bonds
hydrogen complementary base pairs
- :




9

, -




differences between RNA and DNA
-structural
-




TYPES OF RNA AND DNA




provisionI
=
1) MRNA-messenger RNA
found
· made in the nucleus
using DNA as a template · in the nucleus and
packaged in structures
transports code for protein synthesis to ribosome called chromosomes in association with histone proteins




I
2) tRNA-transfer RNA 2) mtDNA- Mitochondrial DNA
found
· made in nucleus and its function is to
bring · in Mitochondria and are ring shaped
amino acids to ribosome for protein inherited from mother only (found in egg cell)
synthesis ·


J 16 500 base pairs
rRNA-ribosomal RNA
minsets or




endosympathetic theory

, The function of DNA
carries the code for protein production . This code is passed on from parent to
offspring
and is therefore known as hereditary material . The code is carried on the
genes

DNA (STR) important concepts :


non-coding >
-


different species have different numbers of
&
chromosomes
-
I cell in the
body has the exact copy
- -




every
of DNA
gene
In the
>
-

body cells the chromosomes come in

pairs
DNA REPLICAT ION
↳ known as semi-conservative replication
> interphase
In
as
-




cytokinesis
the newly formed DNA , she strand is new - >
-
goth
and the other is conserved from original DNA mitosis/



·
Meiosis


PROCESS :
-




I
G DNA unwinds and unzips . -NA

E
↑




② I bonds between complementary bases break. replication
-




· ③ organelle
+
.
catalyzed by the enzyme hellcase rowth
-




replication
& free DNA nucleotides in nucleus will le next to their
j complementary base. [A=T and G =
C)
⑤ H bonds form between complementary bases and sugar phosphate backbone reforms
&
⑳ DNA can only replicate in the 5' to 3 direction (the 5'strand is called the leading Strand


·
.




and nucleotides are laid down in a continuous manner
& The 3'strand nucleotides down discontinous
is called
lagging strand
the + are laid in a

manner . (i .


e in
fragments
A T




I &
- template
jAT-


·
E
In
GC
GC
replication
= & GC

original
&
GC
new
G
new
C


-

2 new Identical DNA strands
PCR Technology
:



↳ polymerase chain reaction

blotechnology process used to amplify a sample of DNA .
-




/




y?
1. forensics to make more DNA Found at a crime scene .


amplify genes to be used
I . in recombant
technology -
.
3 Inexpensive and fast .