1.3-16

Question 1

phospholipid bilayer

Answer 1

• amphipathic properties –> hydrophilic and hydrophobic parts
  -Forms a liposome –> tails attracted to one another
  -Forms basis of all cell membranes
  -Primary function to form a barrier through which ions and hydrophilic molecules cannot easily pass

Question 2

Membrane Proteins

Answer 2

• the more active a membrane, the more proteins

Question 3

Peripheral Proteins

Answer 3

Hydrophilic on surface, not embedded, attached to surface of integral proteins (reversible attachment), some have single hydrocarbon chain attached.

Question 4

Integral proteins

Answer 4

Hydrophobic on at least part of their surface. Includes transporters, linkers, channels, receptors, enzymes,

Question 5

Cholesterol

Answer 5

Def: type of lipid in animal cells

Functions

helps w membrane fluidity

interferes w interactions of membrane to allow membrane to stay in higher temp

***lipids melt in high temp and stiffen in cold

Question 6

Prophase

Answer 6

DNA supercoils and chromosomes condense, Chromosomes are comprised of genetically identical sister chromatids joined at a centromere, Paired centrosomes move to opposite poles of the cell and form microtubule spindle fibers, nuclear membrane breaks down.

Question 7

Metaphase

Answer 7

Microtubule spindle fibers from both centrosomes connect to the centromere of each chromosome, Microtubule depolymerization causes spindle fibers to shorten in length and in contact, this causes chromosomes to align along the center of the cell (equatorial plane).

Question 8

Anaphase

Answer 8

Continued contraction of the spindle fibers causes the genetically identical chromosomes to split, Once the chromatids split, they are each considered individual chromosomes, The genetically identical chromosomes move to opposite poles.

Question 9

Telophase

Answer 9

Once the two chromosome sets arrive at the poles, spindle fibers dissolve, chromosomes decondense, Nuclear membranes reform around each chromosome set.

Question 10

Cytokinesis

Answer 10

Movement of cell. Cell divides and the cell cycle restarts. Cytokinesis occurs after mitosis and is different in plant and animal cells.
In animal, plasma membrane is pulled inwards around the equator of the cell, forming a cleavage furrow.
In plant, vesicles are fused to form a cell plate in the middle of the cell. With the fusion, a separate membrane is formed

Question 11

Endocytosis

Answer 11

substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material.

Question 12

Exocytosis

Answer 12

Vesicles from the inside fuse with the membrane, and release secreted material. I.e. waste

Question 13

Simple diffusion

Answer 13

Spreading out of particles in liquids and gasses that happens because particles are in continuous random motion. – Think color dye experiment from bio class.

Question 14

Facilitated Diffusion

Answer 14

ions and other particles that cannot easily pass through the membrane have to use transport channels.

Question 15

Osmosis

Answer 15

is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential to a region of low water potential

Question 16

Active transport

Answer 16

DEF: uses ATP to move from low to high concentration (against gradient)

Question 17

Chemical Evoluction appearance of first cells

Answer 17

1Early earth acidic, NaO2
2Earliest cell
3Photosynthetic archaea
4Rapid oxygen increase
5Evolves small archaea that uses O2 to break down organic compounds and energy
6Large anaerobes archaea endoyotes small 02
7Formed endosymbiotic relationship

Question 18

Cell Theory

Answer 18

All living things are composed of cells, cells are the smallest units of life, cells only come from pre-existing cells

Question 19

RNA World

Answer 19

RNA world hypothesis proposes that a world filled with RNA-based life predates current DNA-based lifeforms. RNA has two key qualities that allow it to function
–self replication (RNA able to store information in a sequence composed of four recurring nucleotides)
–Act as a catalyst (Modern cells use RNA catalysts called ribozymes to remove introns from mRNA)–speeds up chemical reactions

Question 20

Biogenesis

Answer 20

Biogenesis describes the principle that living things only arise from other living things by reproduction (not spontaneous generation)
-Broths stored in vessels with long tubing (no external dust could pass)
-Broths boiled to kill any microorganisms present
-Growth only occurred if the flask was broken open/exposed to outside

Question 21

Endosymbiotic Cell Theory

Answer 21

Eukaryotic cells may have evolved when multiple cells joined together into one. They began to live in what we call symbiotic relationships.
Evidence
M-Membranes
A-Antibiotics
D-Division
D-DNA
R-Ribosome

Question 22

Cell Cycle

Answer 22

Process by which a cell undergoes division, involving multiple stages, like G1, G2, mitosis etc. Division is needed whenever two genetically identical cells are required.

Question 23

Mitosis

Answer 23

Division of the nucleus into two genetically identical daughter nuclei. These cells will furthermore be fully identical. Before this can occur, DNA in nucleus must be replicated via interphase.

Question 24

Interphase

Answer 24

Mitochondria number goes up.

Interphase consists of three separate stages
Interphase: G0 - rest
Interphase: G1 - growth - even organelles need to grow in cell
Interphase: S - synthesis - replication of DNA; daughter cells need to be copied
Interphase: G2 - growth & prep for division - 2 centrioles prep for division

Question 25

Cyclin

Answer 25

A group of proteins called cyclins ensure that tasks are preformed at the correct time and that the cell only moves into the next stage when appropriate.

Question 26

Cyclin functions

Answer 26

Cyclins bind to enzymes called cyclin dependent kinases (CDK). These kinases then become active and attach to phosphate groups to other proteins in the cell. The attachment of phosphate triggers the other proteins to become more active and carry out the tasks specific to the cell cycle.

Question 27

Checkpoints

Answer 27

Cyclin D: G0 -> G1- initiate cell cycle
Cyclin E: G1 -> S - Prepares for DNA replication
Cyclin A: G2 -> Prophase - DNA repair and doubles organelles
Cyclin B: Metaphase ->Anaphase - Makes sure chromosomes are aligned

Question 28

Cancer and Tumor Formation

Answer 28

Mutagens, oncogenes, and metastasis are involved in the development of primary and secondary tumors. Tumors are abnormal groups of cells. In some cases, cells adhere to each other and do not invade nearby tissues, these are called benign tumors.
Other tumor cells can detach and pass through the bloodstream and spread to other areas.
The few genes that become cancer causing after mutating are known as oncogenes. In a normal cell oncogenes are involved in the control of the cell cycle and cell division.

All mutagens are carcinogens, both chemical mutagens and also high energy radiation such as x-rays and short wave ultraviolet light. Metastasis is the movement of cells from a primary tumor to set up secondary tumors in other parts of the body

Question 29

Hormone binding sites

Answer 29

-Example of a membrane protein
-Helps deal with hormones

Question 30

Immobilized enzymes with active site on the outside

Answer 30

Helps transport insoluble materials
-Example of membrane protein

Question 31

Cell Adhesion

Answer 31

Forms tight junctions between groups of tissues and organs
-Example of membrane protein

Question 32

Cell to Cell communications

Answer 32

Cells get close to each other to communicate or transfer information between one another
-Example of membrane protein

Question 33

Passive transport

Answer 33

Allows hydrophilic particles across by facilitated diffusion
-Example of membrane protein

Question 34

Pumps or active transport

Answer 34

-Uses ATP to move particles across the membrane
-Integral proteins: are located INSIDE the bilayer, hydrophobic on at least part of their surface
- Peripheral proteins: NOT EMBEDDED, hydrophilic on the surface
an example of a membrane protein