Unit 1 Flashcards
Describe the 3 main components of cell theory:
- All organisms are made up of cells.
- All cells come from pre-existing cells.
- Cells are the most basic and fundamental unit of life.
Cells are the smallest entity of life capable of (list all 4 points):
- Self-replication (mitosis).
- Storing and transmitting information.
- Maintaining separate internal/external environments.
- Harnessing and transforming energy.
All cells:
a) store and transmit information - have a molecular blueprint of information.
b) have a boundary/plasma membrane
c) convert energy into a usable form for the cell
Explain the difference between prokaryotic and eukaryotic transcription + translation.
Since prokaryotes have no nucleus, the process of transcription and translation happen co-currently. Prokaryotic transcription happens in the cytoplasm. Eukaryotic transcription happens inside the nucleus, translation in the cytoplasm.
In prokaryotic (bacterial) transcription, a sigma protein binds to RNA polymerase, recognizes the promoter sequence and leaves after the RNA pol. binds to the promoter.
In eukaryotic transcription, RNA pol II binds to the TATA box binding protein because it can’t recognize the promoter (TATA box) on its own. Eukaryotic mRNA also has a 5’ cap, poly-A tail, and introns that are spliced out by splicesomes.
What do eukaryotes have that prokaryotes do not?
A nucleus, membrane bound organelles, the ability to begin DNA replication at many sites, multicellular organisms.
What do prokaryotic cells (bacteria) have that eukaryote cells don’t?
A peptidoglycan cell wall, DNA plasmids that can be transmitted through horizontal gene transfer, and the vast majority of bacteria have 2 membranes.
Why are cells different sizes?
They must be regulated to minimize survival issues.
What causes genetic diversity in eukaryotes?
Sex (meiosis & haploid cells).
Most (not all) eukaryotes are capable of sex, even if they reproduce asexually most of the time.
Why is it problematic if a cell’s surface area: volume ratio is too low?
(I.e., the cell is too big)
There will not be adequate cell membrane compared to the cytoplasmic volume, which means that the space available to receive materials is too low.
How does a cell adapt to a surface area: volume ratio that is too high?
- Inward folding or outward profusion of the membrane
- Changing shape.
What issues might an increased cytoplasmic volume cause?
Adequate volume of substances inside the cell may be diluted.
What adaptations might cells use to overcome dilution issues?
Cytoplasmic streaming in plants
- protein mediated movement and mixing of cytoplasm
vesicle/organelle trafficking on a microtubule highway in animal cells
If cell size increases, how is diffusion affected?
An increased cell size means that relying on diffusion to move molecules is impractical.
How does a cell overcome impractical diffusion?
Compartmentalization.
“An unequal charge distribution between 2 atoms” describes:
And “an unequal charge distribution over a whole molecule” describes:
a) bond polarity
b) molecule polarity
What is the requirement for a hydrogen bond?
A hydrogen atom bonded to an electronegative atom.
Why is a polymer said to have directionality?
It has two chemically distinct ends and has structural polarity.
Describe how permanent dipoles are formed.
If there is a large polarity difference between molecules within a covalent bond, then a partial charge is left on each atom, making them both permanent dipoles.
How does an induced dipole form?
When a polar molecule gets close to a non-polar molecule, the electrons of the non-polar molecule are repelled and a dipole is induced.
What kind of bond(s) is between 2 water molecules?
a hydrogen bond and a permanent dipole - permanent dipole interaction.
What is the difference between a PD-PD interaction and an ion-PD interaction?
One of the PD molecules is replaced with an ion carrying a FULL charge.
