Lecture 1 - Principles of cell function Flashcards
2 types of cells
Prokaryotic (Bacterial)
Eukaryotic (Animal)
5 unique features of a prokaryotic cell
Flagella
Pili
Cell Wall
Capsule
Endospores
What is the flagella?
Antennae of bacterial cell - tries to gauge external environment (is there something near that is important for nutrition purposes)
What is the pili?
The “hairs” that allow bacterial cells to attach to membranes to cause infection
Cell wall
Very thick
Role of Capsule
Prevents cell from drying out
Endospores are where, what, for? resistant to?
Within the cell wall
Walls very thick
For survival under harsh conditions
Resistant to various degrees to heat, desiccation (removal of moisture), freezing, toxic chemicals
Eukaryotic cells have no…
Pili, capsule
Eukaryotic cells have a
Well defined nucleus - contains nucleolus
Cytoplasm - number of organelles
DORA: Prokaryotes
D (DNA): DNA is naked, circular
O (Organelles): No nucleus, no membrane-bound
R (reproduction): Binary fission, single chromosome (haploid)
A (Average size): Smaller
What is binary fission?
Asexual reproduction where 1organism becomes 2, 2 becomes 4 and so forth
DORA Eukaryotes
D (DNA): DNA is bound to protein, linear
O (Organelles): Has a nucleus, membrane-bound, 80s ribosomes
R (Reproduction): Mitosis and meiosis, chromosomes paired (diploid or more)
A (Average size): Larger
In mitosis, daughter cells have … number of chromosomes as parent
Same
In meiosis, what happens with the cell?
Divides cell in 2 - 23 chromosomes each
DIfferent names for a membrane
Cell membrane, cytoplasmic membrane, plasmalemma, phospholipid bilayer, lipid bilayer
Cells are …permeable
semipermeable
if it wasn’t, anything could come in or out. only certain molecules are allowed in
Cells have the ability to…
Engulf
Another word for when a cell uses its plasma membrane to engulf a large particle
Phagocytosis
Interface of cells is between what kind of environments
Internal and external
3 Functions of the boundary in a membrane
- keeps nutrients in the cell,
- helps retain transported substances - useful substances are kept within the cell for use
- Excretion of unwanted substances
Interface between the environments
Cells respond to changes in the environment
Receptors help identify substances needed by the cell
Then, secretion of hormones or neurotransmitters
2 Major plasma membrane functions
- Receptors that have specific domains on it means only a certain molecule can attach on it e.g. if a mutation on the insulin receptors occur, the receptor may not be able to detect the insulin
- Anchors - hold certain proteins e.g. can trap mitochondria to cell membrane for energy purposes.
The cell membrane contains … that has a hydrophilic and hydrophobic part
Phospholipid bilayer
The reason why phospholipids have a hydrophilic and hydrophobic part to it is because…
Phospholipids
What is the protoplasm?
The cytoplasm and nucleus
The 2 faces/surfaces of the membrane
Protoplasm surface, face (P-face)
External surface, face (E-face)
The p-face and e-face contain what?
The intra-membranous particles that are proteins
Differences between the e-face or p-face and the e-surface or p-surface
The outside part of the cell membrane is the e-surface. It is hydrophilic
The inner part of a cell membrane when “unzipped” is the e-face. It is hydrophobic
P-face and e-face contain intramembraneous particles that are proteins
The cell membrane has 2 specific features - 2 dark lines and then a transparent zone in between them. What are these called?
The 2 dark lines are called the electron dense.
The transparent zone is called the electron lucid gap
Since the outsides of the cell membrane are hydrophilic, does a molecule that is soluble in water easily in water move freely into the cell?
Yes but since the e-face and p-face are hydrophobic, they will determine whether the entered molecule is important. If so, it will let it through. If not, it will repel it away.
Fluid mosaic model
States that membrane proteins are highly mobile - wherever the need for protein is, it can move there in 3 dimensions.