Please enable JavaScript.
Coggle requires JavaScript to display documents.
Cells, Biological Molecules, Nucleic Acids and Protein Synthesis, Enzymes,…
Cells
Structures found in BOTH plants and animals
Nucleus
cell surface membrane
Mitochondria
Golgi apparatus
Rough ER
Smooth ER
ribosomes
Cilia and flagella
microscopes
Light microscope
Resolution:200 um
Electron microscope
Resolution: 0.5um
Magnification: Image size/actual size
viruses
Not living things
no cell surface membrane
no cytoplasm
no ribosomes
replicate only in host cells
Structure
DNA or RNA genome
Capsid: a protective protein coat (made of capsomeres)
envelope made of phospholipids (present in some viruses)
animal
organelles found only in animal cells
Centriole
Lysosomes
microvilli
plant
organelles found only in plant cells
Cell wall
plasmodesma
chloroplast
Thylakoid
grana
permanent vacuole
measurement
1mm=1000um
1um=1000nm
bacteria
Prokaryotes
Structures always present
cell wall containing PEPTIDOGLYCAN
cell membrane
cytoplasm
circular DNA
ribosomes: 70S
Structures sometimes present
Flagellum for LOCOMOTION
capsule to slime layer
Infolding cell surface membrane:1)photosynthesis 2)nitrogen fixation
Plasmid: small circular DNA that contains few genes, including ones that give antibiotic resistance
Pili: used to interact with other cells- including sexual reproduction
Biological Molecules
monosaccharides
ring structure
energy
Bonds
proteins
lipids
polysaccharides
Biological tests
disaccharides
Structure
Water
Nucleic Acids and Protein Synthesis
Nucleotide
ATP(adenosine triphosphate): A type of nucleotide
Structure
adenosine
adenine(base)
ribose (pentose sugar)
Three phosphates
AMP: one phosphate; ADP: two phosphate
Structure
nitrogen-containing base
Purine: double ring
adenine & guanine
Pyrimidine:single ring
thymine, cytosine, &uracil
DNA: A T C G; RNA: A U C G
phosphate group
gives nucleic acid its acid nature
pentose sugar
Ribose: RNA
Deoxyribose(one fewer oxygen atom than ribose):DNA
GENE MUTATIONS
Structure of DNA
Two polynucleotide chains form a DOUBLE HELIX
Antiparallel: Two chains run in opposite direction
one run in 5' to 3' direction; the other 3' to 5'
5' and 3' refer to carbon atom 5 and 3 of the pentose sugar
HYDROGEN BOND between complementary bases hold the two chains together
TWO hydrogen bond: A-T
THREE hydrogen bond: C-G
Complementary base pairing: A always pair with T; C with G
A complete turn of the double helix: every 10 bases
Distance between the two backbone is always THREE rings wide
purine(2 rings) +pyrimidine(1 ring)
sugar phosphate backbone
pentose sugars and phosphates are linked by phosphodiester bonds
RNA
SINGLE polynucleotide strand
Function: Protein synthesis
Three types
messenger RNA(mRNA)
unfolded
transfer RNA(tRNA)
folded up into complex structure
ribosomal RNA(rRNA)
DNA REPLICATION
occur in S phase of the cell cycle
Semi-conservative replication PROCESS
Unzipping: Break the hydrogen bonds between complementary bases and unwind the two strands.
A DNA polymerase(enzyme) attaches to each strand and adds one nucleotide at a time.
DNA polymerase copy in the 5' to 3' direction
Leading strand: the parent strand that runs in the 3' to 5' direction
Lagging strand: the parent strand that runs in the 5' to 3' direction
Okazaki fragments: a series of short fragments produced
DNA ligase (1) connect all the new nucleotides with phosphodiester bonds (covalent) and (2)connect Okazaki fragments
TYPES of DNA replication
Semi-conservative replication
DNA molecule is copied two form two identical molecules, each containing one strand from the ORIGINAL molecule and one NEW synthesised strand
conservative
Parent DNA molecule remain at the end of the process. 2. A new molecule with two new strands will be made.
PROTEN SYNTHESIS
TRANSCRIPTION
DEFINITION: Copying the genetic information in a DNA molecule into a complementary strand of mRNA; a single strand of DNA is used as the template, called the template strand, or transcribed strand
LOCATION: nucleus
Process
RNA polymerase(enzyme) attaches to beginning of the gene to be copied
RNA polymerase unwinds the DNA of the gene
DNA helices(enzyme) breaks the hydrogen bonds between two strands
create two single-stranded sections
As RNA polymerase moves along the gene, nucleotides found free in the solution approach and hydrogen bond with their complementary nucleotide in the DNA.
Each nucleotide joins to the growing mRNA molecule with a phosphodiester bond
Once phosphodiester bond is formed, hydrogen bonds of that part is broken.
When a stop triplet is reached, RNA polymerase will release the completed mRNA
RNA processing: In EUKARYOTES, mRNA(primary transcript) will be modified before leaving the nucleus.
mRNA/ modified mRNA leaves the nucleus through a nuclear pore in the nuclear envelope
RNA PROCESSING
RNA splicing: the removal of INTRONS, or intervening sequence (non coding sections of an RNA transcript)
Alternative splicing: primary transcript molecule can be spliced in different ways to produce different mRNA transcript
One gene can code for several different proteins or different forms of the same protein
EXONS: nucleotide sequences after introns are removed
Exons have to be joined together
TRANSLATION
DEFINITION: A stage in protein synthesis during which a sequence of nucleotides in mRNA is translated to corresponding sequence of amino acids to form a polypeptide chain.
LOCATION: ribosome in the cytoplasm
GENETIC CODE
Triplet code
Three bases code one amino acid
There are 64 different triplet codes(4^3)
Some amino acids are coded by more than one triplet
Ex:cysteine is coded by ACA and ACG
There are 20 types of amino acids
The code is universal
Each triplet codes for the same amino acids in all living things
Punctuation code
Stop triplet: mark the end of a gene
Start triplet: signal the start of a gene
Ex: TAC
Enzymes
Mode of action
lock and key
induced fit
active site
inhibition
factors affecting enzyme action
Immobilized Enzymes
Cell membranes and Transport
structure
function
fluid mosaic model
active transport