Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cell Biology > Unit 1 Exam > Flashcards

Unit 1 Exam Flashcards

(95 cards)

Start Studying
1
Q

Definition of a cell

A

the basic structural unit of living organisms that can perform the functions characteristics of life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What did Hooke do for cell biology?

A

observed slices of cark through the microscope and named cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What did Van Leeuwenhoek do/

A

produced a better microscope and was able to observe living cells for the first time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What did Schwann do?

A

came up with the cell theory in which plant and animal tissues are composed of cells and stated that all organisms consist of one or more molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How did Virchow expand the cell theory?

A

he stated that all cells arise from pre-existing cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What sciences does cytology stem from and why?

A

cytology - the study of the structure of cells
biochemistry - study of the chemicals in cells and the protein structure and function
genetics - study of information in DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is light a particle or a wave?

A

light can behave like both a particle and a wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a photon?

A

a particle of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the relationship between energy and wavelengths?

A

they have an inverse relationship - a photon with higher energy has a short wavelength and vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What wavelengths are visible light?

A

400-700 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the limit of resolution for the human eye?

A

about 0.5 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the limit of resolution for the light microscope?

A

about 200 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the limit of resolution for the electron microscope?

A

about 0.2 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Diffraction vs Interference

A

diffraction - waves bend when they go through a slit
interference - waves combine or reinforce to cancel each other out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do lenses do?

A

they bend light to a focal point so you can see

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What determines focal length?

A

shape of lens, refractive index of lens, medium in which it is immersed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is angular aperture?

A

how much light leaving the specimen is gathered by the lens (helps determine the sharpness/ how detailed the picture is)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is numerical aperture, how is it calculated, and what does it do?

A

measure of how quickly light moves and how much waves bend.
calculated: angular aperture x refractive index of the medium surrounding the specimen -
a higher numerical aperture means it is a better lens and has a higher resolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the parts of a light microscope?

A

light source, condenser lenses, objective lenses, intermediate lenses, ocular lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is Brightfield microscopy?

A

microscope that passes light directly through the specimen - often requires stain to create contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is phase contrast?

A

microscope enhances contrast in unstained cells through amplifying refractive index within specimen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is differential interference contrast microscopy?

A

when no staining or fixation is used but optical modifications exaggerate differences in refractive index to create contrast
- uses difference in brightnesses to show the contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is fluorescent microscopy?

A

shows the locations of specific molecules in cells substances absorbing UV radiation and emitting visible light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is confocal microscopy?

A

uses lasers and special optics to illuminate beam on a single plane within the specimen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is TEM?
Transmission electron microscopy - image is formed by electrons that pass through the sample
26
What is SEM?
scanning electron microscopy - image is formed from electrons deflected off the surface sample
27
What do microtomes and freeze fractures do?
microtomes - makes very thin sections of specimen like deli meat freeze fracture - cuts open membranes in the middle both these tools make the pictures better
28
What are the biologically important properties of water?
high specific heat, high surface tension, high heat of vaporization, polar molecule, cohesive, universal solvent
29
What is self-assembly?
how proteins assemble themselves using their primary structure as a template
30
What kinds of bonds hold the amino acids in primary structures together?
strong covalent bonds
31
What kinds of non-covalent interactions are used in self-assembly?
hydrogen bonds, ionic interactions, van der waals forces, hydrophobic interactions
32
What are disulfide bonds?
bonds that form between cysteines and S.
33
What do the noncovalent interactions do?
fold the macromolecules and assemble larger structures in the cells
34
What are molecular chaperones?
proteins that help with self-assembly by holding and preventing polypeptides from interacting with things they are not supposed to
35
Does self-assembly only occur in proteins?
no, they can occur in other complex structures
36
What is the tobacco mosaic virus?
an example of self-assembly in which one strand of rna and 2130 identical molecules of coat proteins can spontaneously assemble into a functional virus particle
37
What are the levels of cellular structure?
small organic molecules, macromolecules, supramolecular structures, organelles, entire cell
38
What are the purines and what are they made of?
adenine and guanine and they are two rings structures
39
What are the pyrimidines and what are they made of?
thymine, cytosine, uracil and they are singular ringed structures
40
What is a nucleotide made of?
phosphate group, sugar, and nitrogenous base
41
What is a phosphodiester bond?
covalent bond that forms between two nucleotides
42
What holds DNA together?
hydrogen bonds
43
How many pairs of hydrogen bonds do A and T have?
2
44
How many pairs of hydrogen bonds do G and C have?
3
45
What is a gene?
a piece of DNA that is transcribed into RNA
46
What does RNA polymerase I do?
makes most rRNAs
47
What does RNA polymerase II do?
makes mRNA
48
What does RNA polymerase III do?
makes tRNA and one type of rRNA
49
What is a promoter and what does it do?
usually a sequence of T's and A's called the TATA box - this is where RNA polymerase binds when starting transcription
50
What are enhancers and what do they do?
DNA sequences that bind transcription regulators and increase the likelihood that transcription will occur in the right place.
51
What is the 5' cap?
a post-transcriptional modification that is a guanine nucleotide that contains an extra methyl group that is attached to the 5' end of the mRNA backwards - aids in stability of mRNA
52
What is the 3' polyA tail?
a post-transcriptional modification of about 50-250 adenine nucleotides that are attached to the 3' end of the mRNA - aids in stability of mRNA
53
How does splicing work?
mature mRNA only consists of exons as the introns are not coded. This is what allows a single gene to produce multiple proteins
54
What is a codon?
the three nucleotides that code for an amino acid
55
What does tRNA do?
brings the amino acid to the ribosome while translation is occurring
56
What does micro RNA do?
21-22 base pair RNA's that regulate gene expression by cause mRNA to be broken down or blocking translation
57
What happens during initiation?
Initiator tRNA and mRNA AUG bind to the small ribosome subunit and the large ribosomal subunit binds over the tRNA
58
What happens during elongation?
a tRNA brings the next amino acids, peptide bonds are created to link amino acids, and the empty tRNA is ejected
59
What happens during termination?
a release factor binds to the stop codon which causes the ribosome to dissociate therefore releasing the peptide chain
60
Which amino acids are hydrophilic?
basic (have a positive charge), acidic (have a negative charge), polar (no charge but has a polar group that is usually NH2 or OH)
61
What is a nonpolar amino acid?
a hydrophobic amino acid that mostly contains a CH3 group
62
What is special about cysteine amino acids?
can form disulfide bonds
63
Describe peptide bonds
covalent bonds between amino acids that are formed by condensation in which the N terminus (amino group) and the C terminus (carboxyl group) bind together
64
Definition of protein
functional, folded, biologically active
65
Why is a polypeptide not a protein?
it is just a string of amino acids and is not folded or functional
66
Monomeric vs multimeric protein
monomeric - consists of only one polypeptide multimeric - contain 2+ polypeptide subunits
67
Homomeric vs heteromeric multimeric proteins
homomeric - one type of subunit heteromeric - different types of subunits
68
What is a protein's primary structure?
linear sequence of amino acids
69
Why is the primary structure so important?
it creates bonds and interactions that are important for protein folding, such as hydrogen bonds, ionic bonds, hydrophobic interactions, disulfide bonds etc
70
What is the secondary structure?
structures formed from local interactions in the polypeptides creating the alpha helix and beta sheets
71
What is the tertiary structure?
the folded, final, native conformation of the protein due to interactions between the R groups all along the polypeptide chain
72
What is the quaternary structure?
only in multimeric proteins and occurs when multiple subunits are binding together
73
Why are small molecules in proteins?
sometimes there are non polypeptide molecules that bind to proteins and add different functions
74
Are all enzymes proteins?
no, some are RNA
75
What is the active site of an enzyme?
a cluster of amino acids where the catalytic event takes place
76
What is allosteric regulation?
when an enzyme is regulated at a site that is not the active site (the binding of a different molecule changes the shape of the active site rendering the enzyme inactive)
77
What is feedback inhibition?
when an enzyme in a biochemical pathway is regulated by a product of the pathway
78
What does phosphorylation and dephosphorylation do to enzymes?
turns enzymes on and off by the addition and subtraction of phosphate groups
79
What are the three domains of life?
archaea, bacteria, and eukaryota
80
What are archaea?
organisms that live in harsh environments that use L-glycerol cell membranes, contain an isoprene phospholipid bilayer and have hydrocarbon chains of the bilayer that interconnect
81
What are archaea most closely related to?
eukaryotes
82
What are the distinctive features of bacteria?
peptidoglycan cell walls, distinct ribosomes, no organelles, DNA has relatively few proteins associated with it, little RNA splicing occurs
83
What are the characteristics of eukaryotes?
membrane bound organelles segregate function, exocytosis and endocytosis to exchange material w/ environment, linear chromosomes exist w/ large amounts of histone proteins, cells divide through mitosis, complex RNA processing
84
What falls under eukaryotic cells?
animals, plants, fungi, algae and protozon
85
Describe the structure of the nucleus and what it does
nucleus contains the nucleolus which is the structure responsible for making rRNA and the beginning of the assembly of ribosomes - the nucleus is also surrounded by a nuclear envelope that consists of a double membrane w/ nuclear pores that allow movement between the nucleus and cytosol
86
what is refractive index?
measure of the slowing down of light in anything other than a vacuum
87
what is excitation?
filter used to shine light of a particular wavelength onto a fluorescent specimen
88
what does the objective lens do?
gathers light from the specimen
89
What is diffraction?
the phenomenon of waves bending after passing through a slit
90
what does the condenser do?
focuses light on the specimen
91
What is the C terminus?
the last part of a polypeptide strand to be made
92
What is the N terminus?
the first part of a polypeptide strand to be made
93
What is a prion?
a misfolded protein capable of binding normal proteins and refolding them into misfolded
94
What is a halophile?
an organism that grows in high salt concentrations
95
What is a stromatolite?
most conspicuous fossil for most of Earth's history; layers of bacterial communities

Cell Biology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions