Lec 4-6 Flashcards
Major theories
Germ theory of disease: pathogens cause disease
Theory of evolution: natural selection
Cell theory: all cells come from other cells
Natural selection
Certain characteristics are more desirable, so individuals with those characteristics will be to survive and reproduce more
Mutation
Random mistake in DNA replication
Some bacteria are antibiotic resistant. How does it originate?
A) Randomly due to a mutation
B) Randomly due to exposure to antibiotics
C) Natural selection, bacteria developed resistance
D) Natural selection, all non resistant cells were killed
A
Variation is caused by random mutations during reproduction. In this case, the mutation is beneficial for the bacteria
How does an entire population of bacteria become antibiotic resistant?
A) Randomly due to a mutation
B) Randomly due to exposure to antibiotics
C) Natural selection, bacteria developed resistance
D) Natural selection, all non resistant cells were killed
D
For a mutation like this, it provides an effect that increases chance of survival and reproduction. So bacteria that have the mutation are able to create more with it and bacteria without it are wiped out.
In humans, development of wisdom teeth is an inheritable trait that is not beneficial and can cause problems. Why have wisdom teeth not been removed by natural selection?
Wisdom teeth have no effect on reproduction, therefore natural selection would not occur. Natural selection pertains to traits that would have an effect on survival and reproduction
Can these molecules get through the cell membrane?
Small, nonpolar
small, polar
large, polar
small, ions
large, ions
Yes
No (usually)
No
No
No
What type of phospholipid has higher permeability: saturated or unsaturated?
Unsaturated
unsaturated lipids have a kink in them that increase permeability
How does temperature effect permeability?
Lower temperatures decrease permeability, higher temperatures increase permeability
Mice that have evolved in cold climates have more _________ phospholipids in their cell membranes.
A) saturated
B) unsaturated
B
Colder climates decrease permeability, so the species evolved to have unsaturated phospholipids to increase permeability
Species that live in the desert have ________ permeability for CO2 than species that live in the tundra.
A) greater
B) lower
C) equal
C
CO2 is a small molecule that can get across the cell membrane by itself so the ability for CO2 to cross is the same
Types of membrane transport
Simple diffusion: Diffuse directly through the cell membrane down their concentration gradient (from high to low)
Facilitated diffusion: Uses a protein channel to diffuse through the cell membrane down their concentration gradient (from high to low), does not require energy
Active transport: Move through the cell membrane against their concentration gradient (from low to high) through a protein channel and uses energy
Types of active transport
Primary: Protein pump moves ions against their concentration gradient. ATP is used
Secondary: Cotransporter
transport protein uses energy from solutes moving down their concentration gradient to power other solutes moving against their gradients
GLUT1 is a transport protein which moves glucose from a high concentration in the blood through the blood brain barrier into brain cells. What type of membrane transport is occurring?
Facilitated diffusion
It uses a transport protein ad its going down its concentration gradient
Sodium Glucose Cotransporter membrane proteins (SGLTs) transport glucose against its concentration gradient from the filtrate in the kidneys and back into the blood. Sodium
(Na+) also moves through simultaneously. What type of transport is this?
Secondary active transport
The glucose is being transported against its concentration gradient and its moving with another solute
