Lecture 8 Study Guide

Question 1

1. What type of microscope allows researchers to observe organelles?

Answer 1

electron microscope

Question 2

2. List three advantages of light microscopy over electron microscopy.

Answer 2

1. labeling individual cellular molecules or structures w/ fluorescent markers has made it possible to see such a structure w/ increasing detail
2. both confocal and deconvolution microscopy have produced sharper images of 3-D tissues and cells
3. a group of new techniques and labeling molecules developed in recent years has allowed researchers to “break” the resolution barrier and distinguish sub cellular structures even as small as 10-20 nm across

Question 3

3. State the main application of cell fractionation.

Answer 3

to study the internal structure of cells and each component’s function

Question 4

4. List 4 features found in all cells on the plant.

Answer 4

1. plasma membrane
2. cytoplasm
3. chromosomes
4. ribosomes

Question 5

State the method by which prokaryote cells

Answer 5

binary fission

Question 6

Define eukaryote and state the method of cell division.

Answer 6

eukaryote: a multicellular organism with a nucleus and membrane bound organelles
method of cell division: mitosis

Question 7

Outline the restrictions placed on the maximum size of a cell.

Answer 7

the ratio between surface area and volume

Question 8

functions of eukaryotic organelles (mitochondria, plasma membrane, smooth ER, cytoskeleton, nucleus, nucleolus, Golgi apparatus, rough ER, ribosomes, chloroplasts, cell wall)

Answer 8

mitochondria: produce energy (ATP)
plasma membrane: act as a selective barrier
smooth ER: synthesis of lipids
cytoskeleton: determines the shape of the cell
nucleus: contains genetic info
nucleolus: rewrite ribosomal RNA and combine it w proteins
Golgi apparatus: modifying, sorting, and packaging of proteins for secretion
Rough ER & ribosomes: protein synthesis
chloroplasts: convert light energy into sugars for the cell
cell wall: protect the cell

Question 9

Define phylogeny.

Answer 9

branch of biology that studies the evolution of organisms

Question 10

Describe the relationship between binomial nomenclature and the Linnaean hierarchical classification system.

Answer 10

the binomial classification gives a organisms their species names (first part is the genus they are apart of and second part is unique to that organism). The Linnean classification starts with species then moves downward (species-genus-family-order-class-phylum-kingdom-domain)

Question 11

In a phylogenetic tree, a dichotomy (aka branch point) represents what?

Answer 11

each branch point represents the common ancestor of the 2 evolutionary lineages

Question 12

Briefly describe the defining traits of the three domains of life.

Answer 12

The 3 domains are made up of bacteria, archaea, and eukaryotes. Bacteria and archaea are both prokaryotes (unicellular). However, archaea and eukaryotes are more like each other than either is with bacteria.

Question 13

Define horizontal gene transfer and list three mechanisms that may allow it to occur.

Answer 13

horizontal gene transfer: a process in which genes are transferred from one genome to another
Mechanisms: exchange of transposable elements and plasmids, viral infections, or fusions of organisms

Question 14

Elaborate on the horizontal transfer of modern day mitochondria and chloroplasts.

Answer 14

between the archaea and eukaryotes, mitochondria and chloroplasts were transferred over to plants form archaea

Question 15

State the name of the polymer found in prokaryotic cell walls. How does it differ from cellulose?

Answer 15

peptidoglycan: a polymer composed of modified sugars cross-linked by short polypeptides

Question 16

State the difference in the location of the peptidoglycan and the plasma membrane in gram-positive vs gram-negative bacteria. How do these two types of bacteria respond differently to antibiotics, in general.

Answer 16

gram-positive: have relatively simple walls composed of a thick layer of peptidoglycan
gram-negative: hace less peptidoglycan and are structurally more complex w an outer membrane that contains lipopolysaccharides
gram-negative is more resistant to antibiotics

Question 17

Define the following items that may be found in prokaryotes:
Capsule
Endospores
Fimbrae
Pili
Positive chemotaxis
Flagellum
Amount and organization of DNA
Plasmids

Answer 17

Capsule: sticky layer of polysaccharides or protein that surrounds the cells
Endospores: resistant cells
Fimbriae: hairlike appendages’
Pili: appendages that pull two cells together prior to DNA transfer
Positive Chemotaxis: move away from toxic chemicals
Flagellum: allows cells to move
Amount and Organization of DNA: Prokaryotes are structurally simpler and have less DNA than eukaryotes
Plasmids: small rings of independent DNA replicating molecules

Question 18

Compare and contrast the process of cell division in prokaryotes and eukaryotes.

Answer 18

prokaryotes undergo binary fission (asexual). eukaryotes undergo mitosis and meiosis

Question 19

Describe two behaviors in eukaryotes made possible by the cytoskeleton.

Answer 19

enables eukaryotic cells to asymmetric forms and change shape as needed

Question 20

Define the following terms:
Photoautotroph
Chemoautotroph
Heterotroph
Saprotroph
Endosymbiosis
Secondary endosymbiosis

Answer 20

Photoautotroph: contain chloroplasts, produce own food and energy
Heterotrophs: absorb and ingest food/energy
Chemoautotroph: obtain energy through oxidation
Saprotroph: an organism that feeds on or derives nourishment from decaying organic matter
Endosymbiosis: a relation between two species in which one organism lives inside the cell or cells of another organism
Secondary Endosymbiosis: ingested in food vacuoles of heterotrophic eukaryotes

Question 21

Outline the three main tenets of cell theory.

Answer 21

1. cells are the most basic fundamental units of life that can do all the functions of life
2. all organisms are composed of cells
3. all cells come from pre-existing cells

Question 22

List four molecules that were present in the atmosphere of the early Earth

Answer 22

1. water vapor, Hydrogen gas, methane, ammonia

Question 23

Compare 4 features shared between prokaryote cells and the mitochondria and chloroplast organelles.

Answer 23

1. cell membranes
2. genetic material
3. ribosomes
4. metabolism