Module 1: An Introduction To Cell Structure And Function

Question 1

Mycoplasma

Answer 1

Simplest cell form of the present-day cells

Bacterium-like, parasitic, diameter = 0.3um

Question 2

Prokaryotes

Answer 2

Cell structure = cell wall ➡️cell membrane ➡️ “soup” of nuclei acids, DNA, RNA, proteins, etc.
Represented by bacteria

Question 3

Bacteria

Answer 3

Simplest organisms found in most areas
Spherical (cocci) or rod-shaped (bacilli)
Thick protective cell wall
In diverse areas and can adapt/survive in even harsh conditions

Question 4

Archaebacteria

Answer 4

Bacteria that can live under harsh conditions ie ocean depths, salt brines, hot acid springs

Question 5

Cyanobacteria

Answer 5

Bacteria that obtains nitrogen directly from atmospheric N2

Question 6

Anerobic bacteria

Answer 6

Thrived when earth’s atmosphere had very little O2

Question 7

Eukaryotes

Answer 7

Cells that have a nucleus and specific organelles within

2 types: plant & animal cells

Question 8

What are the specific organelles of eukaryotic cells?

Answer 8

mitochondria, endoplasmic reticulum, golgi apparatus, lysosomes and peroxisomes in cytosol that also contains a filamentous cytoskeleton

Question 9

How do animal and plant cells differ?

Answer 9

Animal: have a cell membrane and centrioles that play a vital role in cell division i.
Plant: surrounded by cell walls with an underlying plasma membrane; have large vacuoles and chloroplasts that are essential for photosynthesis.

Question 10

In what ways do prokaryotes and eukaryotes differ?

Answer 10

Organisms v. Cell size v. Metabolism v. Organelles v. DNA v. RNA & protein v. Cytoplasm v. Cell division v. Cellular organization

Question 11

Unicellular protists

Answer 11

Simplest of eukaryotes
Single-celled eukaryotic organisms that can utilize photosynthesis or be carnivorous, can be motile or non-motile, can also possess muscle-like contractile bundles, flagella for movement, mouth parts, or pseudopods (leg-like appendages)

Question 12

How did the evolution of multicellular organisms occur?

Answer 12

when cells closely related by ancestry differentiated from each other and developed a specific feature to a high degree, leading to the formation of different parts of a multicellular organism.

Question 13

Epithelia tissue

Answer 13

Structure: cells stacked on top of a basement membrane
Location: lines the inner and outer surfaces of the body
Role: provides protection, absorption, secretion and aids in trapping foreign substances; aggregate to form glands that have specialized secretions.

Question 14

Connective tissue

Answer 14

Role: the “glue” btwn various organs & tissues
Structure: made of an extracellular matrix + fibers + cells (including fibroblasts that produce the fibers and extracellular matrix)

Question 15

Blood

Answer 15

Mix of water, proteins and specialized cells

2 types: erythrocytes (red blood cells) & white blood cells

Question 16

Erythrocytes aka red blood cells

Answer 16

Contain hemoglobin that helps carry 02 from the lungs to the tissues and CO2 from the tissues to the lungs

Question 17

White blood cells

Answer 17

Part of the immune system and help protect the organism from invading microbes

Question 18

Muscle cells

Answer 18

Make mechanical force by contracting.
3 types: skeletal - attached to skeletal structures
Cardiac- make up the heart
Smooth- make up internal organs.

Question 19

Nervous tissue

Answer 19

Made of nerve cells specialized for communication aka neurons
Communicate with each other via special structures called synapses
Neurons transmit info by using electrical impulses and neurotransmitters (specialized chemicals) → makes up the brain, spinal cord, and peripheral nerves → coordinate all body functions, ie. Secretions and movement
Nervous system obtains info from the outside environment via sensory nerves and sensory cells and then it responds accordingly

Question 20

Why is the human nervous system so evolved?

Answer 20

Due to the sheer numbers of neurons, how extensively the connect, how rapidly they transmit and process info and the to ability allow higher level thinking
The way they connect with each other=patterns of behavior

Question 21

What makes up a cell?

Answer 21

6 elements; Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur
Water =70% of the cell
Most of cell= carbon compounds

Question 22

How and why does Carbon make up majority of the cell?

Answer 22

Carbon has unique ability to form large, complex molecules

Carbon + hydrogen + oxygen = the building blocks of the cell → carbohydrates, proteins, lipids

Question 23

What types of organic molecules are found in cells?

Answer 23

Four families of small organic molecules:

1. Sugars
2. Fatty acids
3. Amino acids
4. Nucleotides

Question 24

Amino acids

Answer 24

The building blocks of proteins
An amino group + a carboxyl group + 1 of 20 different side chains
20 different amino acids identified by their side chain

Question 25

How are amino acids classified?

Answer 25

Classified based on side chain into: acid, basic, uncharged polar, or nonpolar amino acids

Question 26

Acidic amino acids

Answer 26

Aspartic acid | Glutamic acid

Question 27

Basic amino acids

Answer 27

Lysine Arginine Histidine

Question 28

Uncharged polar amino acids

Answer 28

``` Asparagine Glutamine Cysteine Serine Threonine Tyrosine ```

Question 29

Nonpolar amino acids

Answer 29

``` Alanine Valine Leucine Isoleucine Proline Phenylalanine Methionine Tryptophan Glycine ```

Question 30

How do amino acids form proteins?

Answer 30

30-100 amino acids joined together = peptide | Several peptides joined = proteins

Question 31

Nucleotides

Answer 31

Form DNA and RNA in the cell A 5-carbon sugar + a phosphate + a base = a nucleotide (Nucleoside = base + sugar)

Question 32

Bases in nucleotides

Answer 32

2 types of bases: purines vs. Pyridines Purines = adenine, guanine Pyridines = cytosine, uracil, thymine

Question 33

Sugars in nucleotides

Answer 33

2 types: ribose vs. 2-deoxyribose

Question 34

How do nucleotides form nucleic acids?

Answer 34

Nucleotides joined together by phosphodiester bonds = nucleic acids If made with ribose sugars = RNA If made with deoxyribose sugars = DNA

Question 35

Other roles of nucleotides

Answer 35

1. Their easily hydrolyzed acid anhydride bonds allow them to carry chemical energy, eg. ATP (adenosine triphosphate) 2. Can join other molecules → coenzymes 3. Can be used as intracellular signaling molecules, eg AMP (adenosine monophosphate)

Question 36

Flow of energy

Answer 36

Electromagnetic radiation (sun) → photosynthesis (plants)→ organic molecules Animals eat plants → oxidize the organic molecules via enzyme- catalyzed chemical reactions → ATP is generated Cells use ATP → macromolecular synthesis and breakdown + heat into the environment Food consumption → broken down into smaller molecules in 3 processes → ATP is produced. Processes occur in the mitochondria Hydrolysis of ATP → energy for biosynthesis ofcellular proteins, lipids, and other macromolecules Repetitive dehydration reactions → small activated precursor molecules assemble into large proteins and nucleic acids

Question 37

Catabolism

Answer 37

The breakdown of larger molecules due to the action of specific enzymes

Question 38

Aerobic generation of ATP

Answer 38

1. Proteins → amino acids. Fats → fatty acids & glycerol. Polysaccharides → sugars. This process is digestion. 2. Smaller molecules enter cells → degraded into cytosol 3. Via glycolysis: carbon and hydrogen atoms of sugars →pyruvate → enters the mitochondria → converted to acetal groups of acetyl coenzyme A (acetyl CoA= large amount of energy like ATP) 3a. Oxidation of fatty acids → acetyl CoA 4. Acetyl CoA is degraded to CO2 and water → ATP is generated

Question 39

Anerobic generation of ATP

Answer 39

Adds an oxygen-requiring step = highly efficient @ extracting energy from food molecules Start: the citric acid cycle (aka Krebs cycle aka tricarboxylic acid cycle) End: oxidative phosphorylation

Question 40

Oxidative phosphorylation

Answer 40

NADH and FADH2 transfer their accumulated electrons into molecular oxygen → large amount of ATP released

Question 41

Nucleus

Answer 41

"Brain" of the cell → regulates gene expression, coordinates protein synthesis, and determines a cell's response to a stimulus

Question 42

Nuclear envelope

Answer 42

Separates the nucleus from the cytoplasm | Made of 2 membranes

Question 43

Chromosomal DNA

Answer 43

Within the nucleus as chromatin→ a tightly wound form that uses histone proteins as anchors to wrap around

Question 44

Nucleolus

Answer 44

A dense body in the nucleus that's thesite of RNA assembly

Question 45

Nuclear pores

Answer 45

Openings in the nuclear envelope that allow contents of the nucleus to be exchanged with the cytosol.

Question 46

Endoplasmic reticulum (ER)

Answer 46

A series of membranous tubes or sacs that lies adjacent to the nucleus Its membrane is continuous with the nuclear envelope's outer membrane Rough ER vs. Smooth ER

Question 47

Rough ER

Answer 47

Has ribosomes on its surface → involved in active protein synthesis Rough ER lumen = the receiving site for the secretion of assembled peptide chains

Question 48

Smooth ER

Answer 48

Tubular and does not have ribosomes on its surface | Has a role in lipid metabolism

Question 49

Golgi apparatus

Answer 49

A system of stacked flattened sacs → modify, sort, and package proteins and macromolecules and prep them for shipment to various parts of the cell for further processing or secretion Transport is via small vesicles that are associated with this particular organelle

Question 50

Lysosomes

Answer 50

Membrane-bound vesicles containing hydrolytic enzymes → responsible for intracellular digestion

Question 51

Peroxisomes

Answer 51

Membrane-bound vesicles containing oxidative enzymes → generate hydrogen peroxide → scavenge oxidative radicals

Question 52

Mitochondria

Answer 52

Sites of power generation →generate ATP by using oxygen and nutrient molecules Contain large # of enzymes that are part of redox reactions involved in the electron transport chain → generating proteins that drive the formation of ATP = an energy source for the all

Question 53

Cytosol

Answer 53

A liquid in the all containing various chemicals and macromolecules → keeps organelles suspended Contains filaments = cell shape, movement, and cell division 3 kinds of filaments: 1 microtubules= 25nm diameter; 2.intermediate filaments = 10nm diameter; 3. Actin filaments = 7 nm diameter