Unit 4: Cell Differentiation, Cell Membrane Structure and Cell Transport

Question 1

Genome

Answer 1

all the genetic life info of an organism.

*Organism in the same species share most of genome.
All cells within an organism share the same genome

Question 2

House keeping Genes

Answer 2

Genes that code for proteins that are associated with basic cellular functions, such as cell regulation, DNA replication, and metabolism

Question 3

Differentiation

Answer 3

different cell types express different genes

Question 4

Gene Expression

Answer 4

The process by which the information encoded in a gene is turned into a function

*Signaling chemicals called morphogens impact gene expression

Question 5

Benefits of Specialization

Answer 5

1) They can focus on fewer tasks

2) They can have a specialized structures and metabolism

3) They can evolve faster in that particular task

Question 6

Stem Cell

Answer 6

A cell that can become anything

Question 7

Process of embryo formation

Answer 7

Fertilization, zygote, embryo, fetus

Question 8

2 hypothesis for how cells formed clusters (multicellularity)

Answer 8

1) A group of independent cells come together
2) When a unicellular organism divides, the daughter cells fail to separate, resulting in an aggregate of identical cells

Benefits**
- provides a survival benefit (strength in #s)
- minimizes predation

Question 9

Properties of stem cells

Answer 9

1) Divide indefinitely to create more stem cells
2) Differentiate to become a specialized cell type

*stem cell niche = where adult stem cells live

Question 10

Totipotent
“entirely potential”

Answer 10

Can become any body cell. Ex. Zygotes

Question 11

Pluripotent
“many problems”

Answer 11

Can become any body cell (but not placenta)
Ex. inner cell mass of a blastocyst

Question 12

Multipotent
“multiple potentials”

Answer 12

Has partially differentiated, but can still become multiple, related cell types
Ex. Adult stem cells, hematopoietic stem cells

Question 13

Induced Pluripotent Stem Cells (iPSC)

Answer 13

Adult cells that can reprogrammed to form pluripotent stem cells
–> can differentiate into all of the cells of the adult body

Question 14

Cell Membrane

Answer 14

Lipid Bilayer
- peripheral protein
- integral protein
- Glyco protein
- cholesterol

Question 15

Phosphate Head

Answer 15

Polar (hydrophilic)

Question 16

Fatty Acid Tail

Answer 16

Non-polar (hydrophobic)

Question 17

Selectively Permeable Membrane

Answer 17

Allows what goes in and out

Question 18

Semi-Permeable

Answer 18

Small, neutral or negatively charged, non-polar except for water can enter

Question 19

Passive Transport

Answer 19

No ATP needed - moves from high to low concentration along the concentration gradient

Question 20

Active Transport

Answer 20

Requires energy (ATP) because materials are moving against the concentration gradient

**is performed by specific carrier proteins on the membrane

Question 21

Diffusion

Answer 21

-Dissolves substances
- Describes the movement from along a concentration gradient

Question 22

Facilitated Diffusion

Answer 22

When a substance is aided across a membrane by ionophores (lipid-soluble molecules)

*high to low
- things are passed through a protein channel

Question 23

Osmosis

Answer 23

Net movement of water molecules across a partially permeable membrane from higher to lower concentration

*water will always move towards regions of more negative water potential ( equals a higher concentration of solute molecules)

Question 24

Hypotonic Solution

Answer 24

Water enters the cell causing it to swell, there is a low amount of solute outside of the cell

TURGID.

Question 25

What is it called when a cell explodes

Answer 25

Cytolysis

Question 26

Hypertonic Solution

Answer 26

The membrane shrinks away from the cell wall, the vacuole collapses and the cell becomes FLACCID.

-There is a high amount of solute outside of the cell

• This state is called plasmolysis and is irreversible!

Question 27

Isotonic Solution

Answer 27

There is the same amount of solute outside the cell as inside the cell

Question 28

Sodium-Potassium Pumps

Answer 28

Exchange of sodium ions for potassium ions across the membrane

Question 29

Protein Pumps

Answer 29

use energy from ATP to move hydrogen ions from inside the cell to outside
- creates a large difference in the proton concentration

Question 30

What are different types of proteins?

Answer 30

Junctions : serve to connect and join two cells together

E
Transport : responsible for facilitated diffusion and active transport

Recognition : may function as a marker for cell identification

Anchorage : attachment points for cytoskeleton and extracellular matrix
T

Question 31

Freeze Fracture Electron Microscope

Answer 31

Rapidly freezing cells then fracturing them to reveal the internal structure of the membrane. This has revealed a mosaic pattern of integral proteins within the lipid bilayer

Question 32

Fluorescence Recovery After photobleaching (FRAP)

Answer 32

• Proves that proteins drift through the membrane
• proteins were labeling with fluorescent marker tabs

Question 33

Unsaturated Fats

Answer 33

• liquids at room temperature, the double bonds prevent them from packing tightly together

Question 34

Saturated Fats

Answer 34

• solid a room temperature (butter, animal fats)
• lack the double bonds allowing them to pack tightly together