Unit 01: Intro to Cell Biology

Question 1

What are the fundamental units of life?

Answer 1

cells

Question 2

what are some examples of single celled organisms?

Answer 2

some bacteria, archaea, protists

Question 3

which type of cells generate electric currents?

Answer 3

heart cells, neurons, electrocytes in eels.

Question 4

what is an example of a cell that produces a substance? which substance does that cell produce?

Answer 4

pancreatic cells produce insulin

Question 5

what is an example of a cell that does mechanical work?

Answer 5

muscle cells

Question 6

which cells pass on genetic instructions to the next generation?

Answer 6

gametes

Question 7

describe the feedback loop of the central dogma.

Answer 7

in order to replicate DNA and transcribe and translate, we need enzymes, but those enzymes had to be produced by those same processes.

so what came first?

Question 8

define differentiation of cells.

Answer 8

while each somatic cell in an organism will contain the exact same genetic material, the expression of the genes is controlled based on the environment of each cell.

Question 9

what is the max resolution of light microscopes?

Answer 9

.2μm

Question 10

what is the difference between resolution and magnification?

Answer 10

resolution tells us what the distance between two specimens has to be to be able to tell them apart under a microscope - essentially the quality of the image

magnification tells us how zoomed in the microscope can get

Question 11

describe how a light microscope works.

Answer 11

a light source from below will shine up into a condenser lens which will condense the light into a beam below the specimen.

the objective lens above the specimen will then make it appear larger, while the tube lens above that will make the specimen EVEN larger (x10)

Question 12

who made the first microscope?

Answer 12

robert hooke

Question 13

who discovered the first cells and named them cellulae?

Answer 13

robert hooke

Question 14

who first discovered microbes?

Answer 14

antonie von leeuwenhoek

Question 15

who discovered that cells are the universal building blocks of life?

Answer 15

matthias schleiden and theodore schwann

Question 16

what is cell theory?

Answer 16

all living cells are formed by the growth and division of pre existing cells.

Question 17

what is a limitation of staining cells with dyes?

Answer 17

cannot stain live cells as it will kill them

Question 18

what is the resolution of fluorescence microscopy? about what size organelle is that?

Answer 18

20nm, ribosome

Question 19

describe how a fluorescence microscope works.

Answer 19

1. light source will shine onto a filter which only allows the wavelength we need
2. the species will emit the wavelength corresponding to the one absorbed
3. that wavelength will go through a beam splitting mirror
4. second filter makes sure that we only see the intended wavelength so that we can see all structures

Question 20

what is the main difference between electron and light microscopy?

Answer 20

electron - uses beam of electrons to visualize specimen, therefore not visible to naked eye

light - uses beam of light to visualize specimen, visible to naked eye.

Question 21

what type of specimen is a transmission electron microscope used for?

Answer 21

a specimen that has been cut up into thin slices and stained with dense heavy metals so that electrons bounce off of it.

Question 22

what type of specimen is a scanning electron microscope used for?

Answer 22

a 3d specimen of which we are looking at its surface

Question 23

which form of life evolved first?

Answer 23

bacteria

Question 24

which form of life evolved second?

Answer 24

archea

Question 25

true or false; e. coli and streptococcus are more related than a human and a pine tree

Answer 25

false, its the other way around!

Question 26

how long ago did bacteria appear?

Answer 26

approximately 3.5 billion years ago

Question 27

are all bacteria single celled?

Answer 27

no, some are multicellular

Question 28

do bacteria have internal, membrane bound structures?

Answer 28

no!

Question 29

what shape are coccus bacteria?

Answer 29

spherical

Question 30

what shape are bacillus bacteria?

Answer 30

rod shaped

Question 31

what shape are spirilloid bacteria?

Answer 31

spiral

Question 32

how do humans mainly get their carbon?

Answer 32

carbohydrates

Question 33

what makes a substance organic vs inorganic?

Answer 33

organic - contains both hydrogen and carbon inorganic - doesn't contain both hydrogen and carbon

Question 34

which bacteria can live completely off of inorganic material?

Answer 34

beggiatoa

Question 35

name some harms of bacteria to humans

Answer 35

- infections like syphilis and strep throat

Question 36

name some benefits of bacteria to humans

Answer 36

- fermentation - antibiotics - medicine - gut microbiome

Question 37

name a multicellular bacteria.

Answer 37

anabaena cylindrica (a blue green algae)

Question 38

what is the purpose of the heterocyst in anabaena cylindrica

Answer 38

to fix atmospheric nitrogen and pass along to other cells in filament

Question 39

what is the purpose of the akinete in anabaena cylindrica

Answer 39

it is a nesting cell of the blue green algae that sinks down to bottom of water body after being filled with nutrients and then filaments in the spring

Question 40

why does phormidium laminosum have such a thick membrane?

Answer 40

they are a photosynthetic bacteria but do not have chloroplasts as photosynthetic eukaryotes do, so they produce much membrane as that is where they carry out their photosynthesis.

Question 41

why do bacteria evolve so quickly?

Answer 41

bc of their rapid proliferation and horizontal gene transfer

Question 42

what is horizontal gene transfer?

Answer 42

the transfer of genetic material between two genomes of organisms that are not parent and daughter. done by transduction, conjugation or transformation

Question 43

are all archaea single celled?

Answer 43

yes!

Question 44

what is the predominant form of life in soil and seawater?

Answer 44

archea!

Question 45

what are some differences between bacteria and archaea?

Answer 45

- chemistry of cell walls - chemical rxns they carry out - types of lipids in their membranes

Question 46

are archea more related to bacteria or eukaryotes?

Answer 46

eukaryotes!

Question 47

how many times larger are eukaryotic cells to bacterial and archaeal cells

Answer 47

1000 to 10 000 times larger

Question 48

what is an example of a carnivorous protist?

Answer 48

didinium

Question 49

which model organism did we use to find out basically everything we know about molecular bio?

Answer 49

e. coli

Question 50

which model organism did we use to study very simple eukaryotic reproduction?

Answer 50

brewers yeast, saccharomyces cerevisiae

Question 51

what did we learn from the model plant Arabidopsis?

Answer 51

- mechanisms in growing towards sunlight - growing in spring - coordination in development and cycle of seasons

Question 52

which model organism did we use to study apoptosis?

Answer 52

c. elegans

Question 53

which model organism has counterparts to 70% of human genes

Answer 53

c. elegans

Question 54

what was drosophila used for?

Answer 54

to study animal genetics and development from zygote to adult

Question 55

why are zebrafish studied?

Answer 55

bc they are transparent for two weeks, allowing us insight into the development of cells, heart and blood vessels

Question 56

why are mice studied?

Answer 56

mammalian genetics, development, immunology and cell biology

Question 57

are humans model organisms?

Answer 57

yes and no.... humans as a system are not but we can use human cells either in vivo or in vitro

Question 58

what is the difference between an in vivo and in vitro cell?

Answer 58

in vivo - impact on the whole organism in vitro - impact on just the cell

Question 59

what was the first ever mRNA vaccine?

Answer 59

covid!

Question 60

before covid, there was another mRNA vaccine being tested and this information was used to expidite the process of engineering the covid vaccine. which disease was the original vaccine targeting?

Answer 60

sars

Question 61

which virus causes covid?

Answer 61

sars-cov2

Question 62

which virus causes sars?

Answer 62

sars-cov1

Question 63

which virus is on its way to become a model system for viruses?

Answer 63

sars-cov2

Question 64

what are homologous genes?

Answer 64

genes on one organism that have close counterpart in another

Question 65

which genes are used to determine relatedness of different organisms?

Answer 65

ribosomal RNA

Question 66

which genes are used to determine relatedness of different humans?

Answer 66

mitochondrial DNA for maternal lineage or Y chromosome DNA for paternal lineage (only can be done in males)

Question 67

which genes existed before the tree of life split into 3 domains?

Answer 67

genes for: dna replication, protein synthesis, lipid synthesis

Question 68

which genomes are the most efficient?

Answer 68

bacterial

Question 69

how many nucleotide pairs and protein coding genes does E. coli have?

Answer 69

4.6 million pairs and 4300 protein coding genes

Question 70

how many protein coding genes does the simplest bacteria have?

Answer 70

500

Question 71

which organism has the largest genome?

Answer 71

algae

Question 72

how much more DNA and protein coding genes do humans have compared to e. coli?

Answer 72

700x more DNA, 5x more protein coding genes

Question 73

why do humans have so much more DNA than e. coli but not that many more protein coding genes?

Answer 73

- some of our DNA regulates gene expression, needed bc we have differentiated cells w different purposes while e. coli doesn't. - humans have introns while bacteria don't! - also just have extra DNA that we don't need but haven't evolved to get rid of it unlike bacteria who evolve fast

Question 74

which genes do we use to determine relatedness of organisms? why these genes?

Answer 74

genes for: dna replication, protein synthesis, lipid synthesis bc they were around before we split into 3 domains, so it is suggested that these genes in modern organisms came from one ancestral gene