Chapter 3 Cells

Question 1

What are the three main parts of a cell?

Answer 1

Plasma Membrane, Cytoplasm and Nucleus

Question 2

What is Cytoplasm and what does it consist of?

Answer 2

Consists of all the cellular contents between the plasma membrane and nucleus. Contains Cytosol and Organelles.

Question 3

What is Cytosol and Organelles?

Answer 3

Cytosol is the liquid portion of the Cytoplasm, is Water and dissolved solutes. Is Intracellular Fluid.
Organelles are little organs with different structures and function within the cell.

Question 4

What is the Nucleus?

Answer 4

The Control center of cells. Contains the genes and controls structure and function of cellular activities.

Question 5

What is characteristics of Plasma Membrane?

Answer 5

Plasma Membrane consists of three type of lipids, and two types of proteins. Has the lipid bilayer. Phospholipids, cholesterol and glycolipids make up membrane, Integral proteins extend into the bilayer, Peripheral proteins loosely attached to the exterior or interior of surface.

Question 6

Describe the permeability of the plasma membrane.

Answer 6

Plasma Membrane has selective permeability to water and non polar(lipid soluble) molecules. NOT permeable to Ions and large uncharged polar molecules. However Ion channels are formed through Integral proteins.

Question 7

What is a solute vs solvent and what is a concentration?

Answer 7

A material dissolved in a fluid is called a solute, the fluid in which it is dissolved in is the solvent. The amount of solute (“stuff”) in a solution is its concentration.

Question 8

What is Passive Process vs Active Process?

Answer 8

Passive process a substance moves down its concentration gradient without using energy - diffusion and Osmosis. Active process uses cellular energy (ATP) to push pass against the concentration gradient.

Question 9

What is simple diffusion vs facilitated diffusion and types?

Answer 9

Simple diffusion - substances diffuses through lipid bilayer from high to low concentration.
Facilitated diffusion is a passive process that uses an integral membrane protein as either a channel or a carrier. As a channel substances moved down the gradient via their specific channel, as a carrier the substance binds on one side of membrane and releases on the other side after changing shape.
*The Hormone insulin does this for glucose.

Question 10

What is Osmosis?

Answer 10

A passive process where water moves by osmosis from area of higher WATER concentration to lower WATER concentration. Passes through lipid bilayer and uses integral proteins that function as water channels.

Question 11

What is Osmotic Pressure?

Answer 11

The pressure exerted on a a plasma membrane by a solution where its particles can’t pass through the membrane.

Question 12

What is Isotonic vs Hypotonic vs Hypertonic Solutions and their relation to Red Blood Cells.

Answer 12

Isotonic - a solution where cells maintain shape and volume. Concentration of solutes are same on both sides.
Hypotonic - a solution that has lower concentration of solutes and higher concentration of water. Vs RBC water enters blood cells quicker than it leaves causing expansion and rupture/burst = Hemolysis.
Hypertonic - a solution that has higher concentration of solutes an low water. Vs RBC moves out of cells by osmosis faster than they enter causing them to shrink. = Crenation

Question 13

What is Active Transport?

Answer 13

An Active process that cellular energy is used to transport substances across the membrane AGAINST the concentration gradient. ATP is used to change the shape of carrier protein which moves substances across gradient.

Question 14

Describe the Sodium-Potassium Pump.

Answer 14

The most important active transport pump.
It pushes Sodium Ions (Na+) out of cells and brings in Potassium Ions (K+).
Doing this the pump maintains a low concentration of Na+ in the cytosol by pumping Na+ against the Na+ concentration gradient out of the cell into extracellular fluid.
The pump moves K+ into cell against the K+ gradient.
Na+ slowly leaks into the cell down the gradient while K+ slowly leaks out following its gradient.
Extracellular fluid has High Concentration of Na+
Cytosol (intracellular) has High Concentration of K+.

Question 15

What is Vesicles and what do they do?

Answer 15

A Vesicle is a small round sac formed by budding off from an existing membrane.
1) Vesicles transport substances from one structure to another within the cells.
2) Takes in Substances from extracellular fluid.
3)Releases substances into extracellular fluid.
All movement by Vesicles requires using ATP making it a Active process.

Question 16

What is Endocytosis and Exocytosis?

Answer 16

They are two types of transports via Vesicles between a cell and extracellular fluid.
Endocytosis moves materials INTO a cell in a vesicle formed from the plasma membrane.
Exocytosis moves materials OUT of a cell by the fusion of a vesicle formed inside a cell with the plasma membrane.

Question 17

What is the Cytoplasm and what is it made up of?

Answer 17

Cytoplasm is all of the cellular stuff between the plasma membrane and Nucleus. Includes the Cytosol and Organelles.

Question 18

What is Cytoskeleton and what is it made up of?

Answer 18

Cytoskeleton is extends throughout the cytosol and is made up of 3 protein filaments.

Question 19

What are the 3 protein filaments that make up the cytoskeleton and function.

Answer 19

Microfilament - provides general support and helps generate movements.
Intermediate filament - helps hold organelles and nucleus in place.
Microtubules - help determine cell shape, movement of organelles and cell division.

Question 20

What is Centrosome?

Answer 20

An Organelle located near the Nucleus. Is the organizing centers microtubules and mitotic spindle which plays a critical role in cell divison.

Question 21

Describe Cilia and Flagella.

Answer 21

Organelles made of Microtubules. 1) Cilia are short hairlike structures that extend from surface of the cell, moves fluid/substances across surface of cells. (Airway, digestion)
2) Flagella - Similar structure to Cilia but much longer, flagella moves entire cells. - Sperm.

Question 22

Describe Ribosomes.

Answer 22

Organelles composed of two subunits containing ribosomal RNA and Protein. They float free in cytosol or attached to Rough ER.
- Are the site of protein synthesis.

Question 23

Describe Endoplasmic Reticulum.

Answer 23

Membranous network of folded membranes. Rough ER is studded with ribosomes and is attached to the nuclear membrane, Smooth ER lacks Ribosomes.
Rough ER synthesis glycoproteins and phosolipids.
Smooth ER synthesis fatty acid and steroids. Releases glucose into bloodstream / In liver inactivates/detoxifies drugs and harmful substances

Question 24

Describe the Golgi Complex

Answer 24

An Organelle, a stack of 3-20 flattened membranous sacs called cisterns. Accepts proteins from Rough ER, forms glycoproteins and lipoproteins, stores, packages and export proteins.

Question 25

What is a Lysosome?

Answer 25

Organelle vesicle formed for the Golgi Complex, contains digestive enzymes. Fuses with and digest contents of vesicles. Digests worn-out organelles = Autophagy and entire cell = Autolysis and extracellular materials.

Question 26

What is Autophagy and Autolysis?

Answer 26

Autophagy is the process of worn-out Organelles are digested. and Autolysis is the process of digesting entire cells. Lysosomes and its enzymes do these process.

Question 27

What is Peroxisomes?

Answer 27

A organelle vesicle that contain oxidative enzymes. Detoxifies harmful substance such as hydrogen peroxide and associated free radicals.

Question 28

What is Proteasome?

Answer 28

A barrel shaped Organelle that contains and enzyme Proteases that cuts proteins.

Question 29

What is the Mitochondria?

Answer 29

The Organelle site of reactions that produce most of the cells ATP.

Question 30

Describe the Nucleus.

Answer 30

Consists of Nuclear envelope with pores, nucleoli and chromatin (chromosomes)
Contains genes which control cellular structure and direct most cellular activities.

Question 31

Describe how protein synthesis works.

Answer 31

DNA contained in genes provides the instructions for making proteins. To Synthesis a protein:
1)Info in specific region of DNA is TRANSCRIBED to produce a specific molecule of RNA.
2)The RNA then attaches to a ribosome where info in the RNA is TRANSLATED into specific amino acids that form new protein.

Question 32

Describe Interphase what it is a part of.

Answer 32

Interphase is first phase of Somatic Cell Division. In Interphase the cell replicates its DNA. Makes additional Organelles and Cytosolic components in anticipation of cell division.

Question 33

What is Mitotic Phase, its role and its stages?

Answer 33

Second phase of Somatic Cell division. Mitotic phase is the replication and distribution of two sets of chromosomes into separate and equal nuclei. Has 4 phases. Prophase, Metaphase, anaphase and Telophase.

Question 34

What is Cytokinesis?

Answer 34

Final stage of Somatic cell Division. It is the division of cells cytoplasm and organelles. Begins late in Anaphase with formation of cleavage furrow - which is an indent of the plasma membrane that grows and splits the cell, creating two separate cells.