Week 1 Lecture Flashcards
What are some characteristics of Prokaryotic cells?
1.No nuclei
2.Single celled
3. Ex: Bacteria and Archaea
4. No membrane bound organnels
5. Smaller than eukaryotes
6. Less DNA than eukaryotes (helps in division)
What are some charactrestics of eukaryotic cells?
They have:
1. Nuclei
2. Single celled OR multicelled
3. Ex: Plants, FUNGI, Humans, Animals
What is common in both prokaryotes and plant cell(eukaryote) ?
They both have cell wall.
What do plants cells have but not animal cells?
1.Cell Wall
2.Vacoules
3.Chloroplats
What are some characteristics of Eukaryotic cell?
- Have nucleus
- Several membrane bound organelles
- Larger size and more complex
What is the role of cell wall?
Tough protective outer layer
What are Vacoules?
2 kinds:
1. Storage
2. Like animal lysosome or Degreation
What are chloroplast?
Used in photosynthesis
What is the theory behind the origins of mitochondria?
- Mitochondria were initially free living aerobic prokaryotes able to use oxygen to help generate atp
- Early Archeaon could not use oxygen to generate ATP.
- Via a process of Ectosymbiosis the bacterial cell was entangled, then over time it managed to get into the cytosol of the cell
- Soon it Endogenised, became a part of the cell. (this was around the same time other organnels were forming in the cell)
What is ectosymbiosis?
A form of symbiotic behaviour in which an organism lives on the body surface of another organism including internal surfaces
What is the E3 theory? And what does it stand for?
Entangle, Engulf and Endogenize
It is a theory that states, An ancient archea entangled an ancient bacterial prokaryote that was able to use oxygen to produce ATP. Soon it was engulfed into the cytosol and Endogenized (becoming a part of the cell)
What is endosymbiont?
Cell that lives inside another cell with mutual benefit.
What is the endosymbiont hypothesis for origins of mitochondria and chloroplasts?
- Both Mitochondria and Chloroplasts have remnates of their **own Genome and genetic system **that resemble modern day prokaryotes.
- Mitochondria and Chloroplasts have kept some of their own protein and DNA synthesis components and these also resemble the prokaryotes too.
- Membrances in mitochondria and chloroplasts often similar to those in prokaryotes and apper to have been derived from engulphed bacterial ancestor.
What were the origins of Eukaryotes?
- Initially, there were only Ancestreal Procaryotes
- Then there were 2 sub groups: Bacteria and Archea
- Bacteria was divided into: Photosynthetic and non-photosynthetic (Mitochondria was a prokaryote that used oxygen hence it was non-photosynthetic)
- Then mitochondria was entangled, engulphed and endogenised by the archeal cell which gave rise to **single celled eukaryotes. **
- Later on chloroplasts entered into some cells which later went on to become Plant cells and the other two remained aminal cells and fungi.
What is a model organism?
A living thing selected for an intensive study as a representative of a large group of species.
What are characterics of model organism?
1.Rapid developement with short life span
2.Small adult size
3.Readily available
4.Tractability: Ease of manupulation or modification
5.Understable genetics
What is genome?
All the DNA or DNA sequences in a cell or Organism, including the dna from mitochondria or nucleus.
What is Transcriptome?
All the RNA or RNA sequences in a cell or an organism at a particular point in time. It changes **constantly **
What is Proteome?
All the protein in a cell or the entire organism at a particular point of time (like a snapshot)
What is Interactome?
All the full set of protein-protein interactions in a cell or organism
What are metabloties?
All the small molecule metabolites in a cell or organisms (glucose, hormones, cholestrol, nutrient wastes etc)
What is Phenome?
All the phenotypes in a cell
What is nucleic acid?
Genetic material in a cell, more like organism’s blueprints
Ex: Deoxyribonucleic acid, ribonucleic acid. (DNA is missing an oxygen)
What are the three parts of nucleotides?
- Pentose sugar
- Nitrogenous base (1 prime is attached)
- Phosphate group (5 prime is attached to this)
What bases are 1 ring?
Pyramidine bases
What bases are 2 rings?
Purines bases
Which are purines and which are pyramidines?
Purines: “Pures are good”
Adenine, Guanine
Pyramidines: Uracil, Cytosine, Thymine (u see the pyramids)
Or remember: Molecular biology is confusing, long is short (ie. longer name is shorter structure rings, shorther names is longer rings)
What is the difference between DNA and RNA
Ribose: has oxygen on 2 prime carbon and has GUAC
DNA: Missing a oxygen of 2 prime carbon
Has ATGC as bases
What is the difference between thymine and uracil?
Uracil has a missing methyl group while thymine has a methyl group on the carbon
What is the difference between a nucleoside and a nucleotide?
Nucleoside: Base + sugar
Nucleotide: Base + sugar + atleast one phosphate group
True/ False:
Nucleoside monophosphate, nucleoside triphosphate, nucleoside triphosphate are all nucleotides
True
(remember this: Nucleoside is sugar and nitrogenous group set aside, while nucleotide is sugar + nitrogenous + phosphate group tied together )
Using what neucleoside?
How is DNA synthesized from?
deoxyribonucleoside triphosphates, (dNTPs) , where N could be A, T, C, G
Ex: dATP, dGTP
Using what nucleotides?
How is RNA synthesized?
NTPs, Ribonucleoside Triphosphate.
Ex: ATP, GTP etc
How are nucleotides tied together?
Using Phosphodiester bonds
What does the side of the last phosphate group called?
5’ end: Becuase this side has a phosphate group attached to the 5’ carbon
What does the side of end with OH group called in the DNA?
3’ end, it has an OH group to the third carbon on the ribose sugar
Instead of drawing structure of DNA strand each time how can you make it simple?
Assume the stand goes as G followed by A followed by T followed by C
5’-GATC-3’
True or Flase: Interaction between molecules is mediated by covalent bonds
FALSE, it is non-covalent bonds, you dont want permanent molecules.
What are the non-covalent bonds present in the inteactions between the molecules in DNA strands?
- Vander- Walls attractions
- Hydrogen bonding
- Electrostatic attractions
- Hydrophopic bonds
Individually they are very week, but together they become quite strong.
True / False:
Base pairing holds the DNA double helix together
True
How many H-bonds exsist between A and T and G and C
A-T: 2
G-C: 3 (sticker than A-T bond)
What are the 3 forces involved in keeping the DNA strands together?
- Hydrogen bonds
- Hydrophobic bonds
- van der Walls attractions
What are the hydrophobic components of DNA?
Base ring structures (Hence they face inside, yet they do form H-bonds)
Where do vanderwalls forces occur in DNA strands?
Between the stackings of the bases
True/ False:
Dna has an energitically favoured conformation
True
What are the two grooves on the DNA?
Major and the Minor grooves.
On which grooves are the most protein contacts made and why?
On the major groove cause the minor groove is too narrow.
True/Flase: Base stacking contributes significantly to the stability to the dna double helix
True
