Chapter 1: Introduction to the Study of Cell and Molecular Biology

Question 1

Explain this diagram(3)

Answer 1

• 1. Mouse model mimicking sickle cell; trying to see if they can fix the tissue; collect skin cells - trying to get them to think and act via treatment with viruses as undifferentiated stem cells. (embryonic-like stem cell–> induced pleuripotent stem cells)
     
     2. next isolated them into individual populations

**mutant= sickle

• gene transfer/therapy to correct mutant.
• only need to change one copy of an allele since it is recessive.
• create a genetic correct then make it diff to blood stem cells.
  3. missing in transfer?
• need t establish in bone marrow therefore present cells there need to be depleted via erradiation.
• then injection added! technically only need one blood cell to re-establish bone marrow.

Question 2

Pluripotent ?

Answer 2

• not capable of sustaining life but will get to the blastocyst stage;

Question 3

Totipotent?

Answer 3

the ability of a single cell to divide and produce all of the differentiated cells in an organism

Question 4

Cell theory??

Answer 4

• all organisms are composed of one or more cells
• cell is the structural unit of life for all organisms
• cells can arise only by division from a pre-exisitng cell (blurry)

Question 5

Give a summary of the basic cell properties! (10)

Answer 5

• functional unit of life
• complexity and organization
• genetic code
• reproduction

=energy requirements: cellular respiration= atp/photosynthesis

• metabolism
• performing mechanical activities such as movment of the cell
• responsive (communication)
• self regulating (homeostasis )
• evolve

Question 6

HeLa??

Answer 6

• first human cells for extended culturing

L> aggressive form of cancer

L> first human cell line …doesn’t need a substrate ie cancer

Question 7

Prokaryotes:

• they are structurally ___, biologically ___.

Answer 7

• simple
• diverse

Question 8

General characteristics of prokaryotes?

Answer 8

• no membrane bound nucleus
• bacteria = ex
• reproduce via binary fission ( dna replicates and they separate anchoring on either side of the cell which then dviding into two parts that have the potential to grow to the size of the original cell) –Asexual
• adapt easily to environment

Question 9

Prokaryotes are sigle or multi-cellular?

Answer 9

single

Question 10

• __% prokaryotes we think exist- they exist in___?

Answer 10

90%

-subterresterial

Question 11

What two domains are prokaryotic?

Answer 11

• Domain Archaea
• Domain Bacteria

Question 12

Domain Archaea??

Answer 12

• methanogens- produce methane as a by product oxygen depleted environments
• halophies - live in high salt concentrations
• acidophiles- live in very acidic environments
• thermophiles- can tolerate extreme temperatures

Question 13

Domain Bacteria?

Answer 13

• Regular bacteria
• Mycoplasma - smallest known cell…contains about 500 genes.. lack cell wall…generally antibiotics attack cell wall synthesis but not in this guy
• Cyanobacteria

Question 14

Characteristics of eukaryotes?

Answer 14

nucleus

• plasma membrane
• m bound organelles
• cytosol
• cytoskeleton

Question 15

Label the parts of the cell

• what type of cell is this?

Answer 15

Question 16

Types of eukaryotic cells?

Answer 16

• unicellular: complex single celled organisms
• multicellular: different cell types for different functions

Question 17

What are features held in common by prokaryotes and eukaryotes?

Answer 17

• plasma membrane of similar cosntruction
• genetic information encoded in DNA using identical genetic code
• similar mechanisms for transcription and translation of genetic information, including similar ribosomes
• shared metabolic pathways (eg glycolysis and TCA)
• similar mechanism of photosynthesis (between cyanobacteria and green plants
• similar apparatus for conservation of chemical energy as ATP ( located in the plasma membrane of prokaryotes and the mitochondrial membrane of eukaryotes)

Question 18

Features of eukaryotic cells not found in prokaryotes

Answer 18

• division of cells into nucleus and cytoplasm, separated by a nuclear envelope containing complex pore structures
• complex membranous cytoplasmic organelles (includes ER, golgi, lysosomes, endosomes, peroxisomes and glyoxisomes)
• specialized cytoplasmic organelles for aerobic respiration (mitochondria) and photosynthesis(chloroplasts)
• presence of two copies of genes per cell (diploidy), one from each parent.

Question 19

Are prokaryotes inferior to eukaryotes?

Answer 19

NO

• ex: we couldn’t survive without bacteria in us…vitamin K is provided for blood clotting via post translational modification…
  ex: bacteria in our intestine provide us with vitamin B which is a cofactor in metabolism of fatty acids.

Question 20

Endosymbiant theory??

Answer 20

• mitochondria and chloroplast may have originated from prokaryotes~

L> size and shape similar to prokaryotes

• dna organization not linear or have histones
• reproduce via bianry fission (within our cells)
• protein synthesis….can do it themselves but not everything~

Question 21

Explain the endosymbiont theory in terms of events that happened.

Answer 21

–two events:

1. Composite event :

L>An anaerobic, heterotrophic prokaryote (archaea) engulfied but not digested an aerobic prokaryote (bacteria)

• the aerobic heterotrophic prokaryote developed mitochondria within it from the aerobic prokaryote it took up.
• pasma membrane invagination occured making the cell pre-eukaryote.
• Then the nuclear envelope precursor developed and an endoplasmic reticulum precursor as well..(primitive eukaryote)
  2. Composite Event:
• no addition of other prokaryotic parts = develops into animal cells, fungal and protist cells
• If it now takes up a photosynthetic cyanobacterium it will develop chloroplasts…and develop into algal and plant cells.

Question 22

What are the mechanisms required for the endosymbiont theory for the cell involved?

Answer 22

• large size and ability to phagocytize

Question 23

Phylogeny of the three domains indicates what?

Answer 23

• nucleotide sequence similarities between representative member of the three primary domains
• used rRNA genes -> WHy?? BECAUSE WE ALL MAKE THEM……ie not all have mito or chloro
• all came from a common ancestor

Question 24

Microbiome?

Metagenome?

Answer 24

• body fauna (total)
• taking microbiome and all of their genomes present then we can match the huge genome to specific genomes of those present

Question 25

Based on the nucleotide sequence of single genes, Woese proposed three major cell linages???

Answer 25

1. Bacteria: include gram (+), gram (-) and cyanobacteria
2. Archaea: include halophiles, thermophiles. methanogens and acidophiles
3. Eukarya: plants, animals and fungi protists

Question 26

Model Organisms:

1. Escherichia coli (bacterium)
2. Saccharomyces (yeast)
3. Arabidopsis (mustard plant)
4. Caenorhabditis elegans (nematode)
5. Drosophila (fruitfly)
6. Mus musculus (mouse)

Answer 26

1. transcription, translation, DNA synthesis
2. least complex eukaryote

L> still has a large number of proteins that are homologous to human proteins

L> can be grown in haploid state (1 copy of genes) …therefore you only have to change one allele to see the affect aka see mutations immediatly

3. extremely small genotype

L> rapid generation time, large seed production, few inches ing rowth (easier to keep in lab)

4. defined number of cells app 100

L> develop according to a percise pattern of cell division that has to do with larval stages

L> short gen time

L> translucent ie you can see whats going on in it.

5. small complex

L> easy to manipulate

L> polytein chromosomes: large chromosomal puffs when translationally active !

L> individual genes can be studied for evolution and gene expression

6. 1000’s of different genetic strains have been developed

L> freez embryos since we cannot house them all! —later use

L> nude mouse: phenotypic characteristics due to surpressed immune sytem!

L> do transplants

Question 27

H1N1 infects?

Answer 27

**Influenza H1N1 infects only human respiratory epithelium?

Question 28

The Human Perspective: The Prospect of Cell Replacement Therapy. Explain it !

Answer 28

• take somatic cell and fuse it with enucleated oocyte
• nucleated oocyte
• allow to develop into blastocyst
• ES cells….5-7 days old blastocyst
• growes ES cellls in culture
• induce them to differentiate into the desired cells
• transplant back into the body

**demethylation prevents them from going back to a somatic cell

Question 29

The Human Perspective: The Prospect of Cell Replacement Therapy:

• Stem cells are ?

Answer 29

• undifferentiated cells capable of self renewal and differentiation
• adult stem cells can be sued to replace damaged or diseased adult tissue

**hematopoietic stem cells can produce blood cells in bone marrow

**neutral stem cells can be used to treat neurodegenerative disorders!

Question 30

Non-cells? aka?

Answer 30

• viruses

Question 31

Non-cells?

• Viruses

L> Obligatory intracellular parasites?

Answer 31

• have to enter a host cell! depend on them for replication

Question 32

Non-cells?

• Viruses

L> Obligatory intracellular parasites

L>characteristics of them?

Answer 32

• virion: infected from outside the cell
• capsid: protien coat that covers the genetic material
• envelop derived from the host cell
• genetic material : only have very few genes
• examples = bacteriophages…which infect bacteria which in turn can infect us.
• host range is extremely small…it is speicfic with what they infect.

Question 33

Examples of viruses?

Answer 33

• human immunodeficiency virus: HIV

L> lipid bilayer

L> reverse transcriptase (turn its rna into dna)

L> RNA

L> gp 120 coat protein

• Adenovirus - capsid subunits
• T-even bacteriophage

L> infect bacteria

L> most complex virus

L> hyperdemic needle shaped body…

L> protein coat

L> nucleic acid

L> most biologically abundant entity on earth

Question 34

Viral Infection

-two types?

Answer 34

• Lysogenic
• Lytic

Question 35

Viral Infection:

• Lysogenic??

Answer 35

• provirus formation occurs aka integration of viral dnal into the host cells genome
• no immediate host cell death

Question 36

Viral Infection:

-Lytic ?

Answer 36

• fairly quick infection
• infected host cell will lyce

Question 37

Explain lysogenic outcome?(3)

Answer 37

• stimulus that causes the cell to lyse and the progeny to be released ->falls into lutic cycle

Ex: UV…progeny will be made and released…able to be in stasisi without being in another bacterium until they bump into another population

2. Animal cell:
   - continual budding out of the cell…it can eventually cause death to the host cell
3. Potential tumor development
   - proto-oncogene promotes cell division normally

L> alteration within the regulatory region -> how the viral region is integrated can cause the gene to be overexpressed

Question 38

How much of our genome is viral?

Answer 38

• 1%
• from a provirus that never left….app 30 million base pairs
• we could not survive as a species of mammals without them
  ex: endo-virus –>it’s genes are essential for placenta development

Question 39

Synthetic biology??

Answer 39

• a field oriented to create a living cell in the laboratory

L> a more modest goal is to develop novel life forms beginning with existing organisms

L> possible applications to medicine , industry or the environment

L> prospect is good after replacing the genome of one bacterium with that of a closely related species