Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MED-103 Biology I (2024-25) > Topic 5: cell structure + function > Flashcards

Topic 5: cell structure + function Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the 2 types of microscopes?

A

1) Light microscope =
- Visible light passes through specimen
- Magnification through lenses
2) Electron microscope =
- Focus beam of e- through specimen / onto surface

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

Factors affecting microscopy image quality

A
  • Magnification = ratio of image size to real size
  • Resolution = clarity = minimum distance 2 points distinguishable
  • Contrast = visible differences in parts of a sample
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe light microscopes

A
  • 1000x size of specimen
  • Resolution = 0.2 µm = 200 nm
  • Subcellular structures = organelles too small
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give light microscopy methods

A

ALL 2D
1) Brightfield = unstained
- Light passes directly through
- Image has little contrast unless specimen has natural contrast
2) Brightfield = stained
- Dye enhances contrast
- Methyl blue
- Require cell to be fixed
3) Phase contrast = unstained
- Enhances contrast by amplifying densities within specimens
- Useful for examining living unpigmented cells
4) Differential interference contrast = unstained
- Like phase contrast = optical modifications to differences in density = almost appear 3D
5) Fluorescence = stained
- Show location of specific molecules by tagging with fluorescent dye/antibodies
- Tags absorb UV and emit light
ONE 3D
6) Confocal = stained
- Uses lasers + optics on fluorescently stained specimens
- Single plane focus illuminated + out of focus subtracted by computer
- Reconstruction of 3D from obtained images

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

Describe electron microscopes

A
  • Magnification 250,000x
  • Can detect structure small as 0.1nm
  • Resolution = 2nm = 100x improvement from light microscope
  • Can detect macromolecules
  • 2 types = TEM + SEM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe TEM

A
  • Focus beam through specimen
  • To study internal structure = 2D image
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe SEM

A
  • Focus beam onto surface
  • Study surface of specimen = 3D images
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe cell fractionation

A
  • Allows isolation of subcellular components = determine organelle function
  • Based on size + density
  • Centrifugation = used to fractionate cells
  • 2 types = differential + density gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe differential centrifugation

A
  • Solvent concentration = stabilizing solvent gradient
  • Multiple centrifugation steps = increase acceleration + time
  • Separation basis = size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe density gradient centrifugation

A
  • Solvent concentration = steep solvent gradient
  • Single centrifugation step
  • Separation basis = density
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Compare prokaryotic/eukaryotic cells

A

ALL HAVE:
- Plasma membrane
- Semifluid cytosol
- Have chromosomes
- Have ribosomes

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

Contrast prokaryotic/eukaryotic cells

A

PROKARYOTES:
- No nucleus
- DNA unbound in nucleoid
- No membrane-bound organelles
EUKARYOTES:
- Nucleus bound by nuclear envelope
- Bigger than prokaryote
- Membrane-bound organelles

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

Define cytoplasm

A
  • Region between plasma membrane + nucleus
  • Has all subcellular structure except nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define cytosol

A
  • Intracellular fluid
  • Excludes organelles
  • Contains ribosomes + cytoskeletal filaments + soluble molecules + water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe plasma membrane

A
  • Selective barrier = allows passage of oxygen + nutrients + waste in/out of cell
  • Phospholipid bilayer
  • Semi-permeable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe nucleus

A
  • Contains DNA of cell
  • Genes in chromosomes = contain directions for protein synthesis
  • Chromosome = complex proteins + DNA = chromatin
  • DNA replication + transcription takes place
  • Replication = before every cell division
  • Transcription = DNA>mRNA
17
Q

Define nucleolus

A
  • Denser area in nucleus
  • rRNA synthesized here
  • After synthesis = assembled with proteins = exit nucleus = form ribosomes
18
Q

Define nuclear envelope

A
  • Encloses nucleus + separating it’s contents from cytoplasm
  • Has nuclear pores
19
Q

Define nuclear pores

A
  • Regulate entry + exit of molecules from nucleus
20
Q

Describe the ribosome

A
  • Made of rRNA + protein
  • Consist of small + large subunit
  • Function = protein synthesis
  • Location =
    1) Free ribosome in cytosol = synthesize cytosolic proteins
    2) Bound to RER = synthesize secreted + membrane-bound proteins
21
Q

Describe the endoplasmic reticulum

A
  • Membranous tubules and sacs
  • Inside space = lumen
  • ER membrane continuous with nuclear envelope
  • 2 types:
    1) SER = lacks ribosomes
    2) RER = has bound ribosomes
22
Q

What is the function of SER?

A
  • Synthesize lipids
  • Metabolizes carbs
  • Detoxifies poison
  • Stores calcium
23
Q

What is the function of the RER?

A
  • Protein synthesis
  • Post- translation modifications = functional
  • Protein sorting = transport + distribute ny producing membrane-bound transport vesicles
24
Q

What are some modifications occurring in RER?

A
  • Polypeptide cleavage = polypeptides activated by enzymes that cleave them = functional = insulin
  • Protein folding = into tertiary structure
  • Subunit assembly = into quaternary structure = functional = haemoglobin
  • Chemical modifications = addition of chemical groups
25
Q

Describe the Golgi apparatus

A
  • Flattened membranous sacs = cisternae
  • Receives transport vesicles from RER
26
Q

What are the functions of the Golgi?

A
  • Protein + macromolecule processing = receives + modifies by adding chemical groups/lipids/carbs
  • Macromolecules sorting /targeting = sort + package biomolecules into transport vesicles > send to other parts of cell
  • Manufacture certain macromolecules = polysaccharides
27
Q

Describe lysosomes

A
  • Membranous vesicle containing hydrolytic enzyme
  • Digests macromolecules = releases parts that can be reused by cell for building new macromolecules
  • Function only at acidic environments
  • Functions = phagocytosis + autophagy
28
Q

Describe phagocytosis

A
  • Intracellular digestion
  • Used by some protists to digest food
  • Macrophages use lysosomes to ingest pathogenic microorganisms
29
Q

Describe autophagy

A
  • Destruction of damaged organelles
  • Recycling cells organic material
30
Q

Describe the endomembrane system

A
  • Important to cell’s compartmental organization
  • Regulates protein traffic + performs metabolic functions
  • Components either continuous or connect via vesicle-mediated transfer
    COMPARTMENTS:
  • Nuclear envelope
  • ER
  • Golgi
  • Lysosomes
  • Plasma membrane
31
Q

Describe mitochondria

A
  • Change energy from 1 form to another
  • Site of cellular respiration = generates ATP from sugars + fats
  • Found in eukaryotic cells
  • Not part of endomembrane system
  • Have double membrane = smooth outer + inner folded cristae
  • Contain own DNA
  • Proteins made by own free ribosomes in mitochondrial matrix
32
Q

Describe a peroxisome

A
  • Specialized membrane-bound metabolic compartment
    FUNCTION:
  • Produce hydrogen peroxide = convert to H2O by enzymes
  • Detoxification = liver peroxisomes detoxify alcohol + harmful compounds
  • Fatty acid breakdown
33
Q

Describe proteasomes

A
  • Giant protein complexes = bind to protein molecules + degrade
  • Short-lived cytosolic proteins + non-functional proteins are attached to ubiquitin = targeted to proteasomefor degradation

MED-103 Biology I (2024-25) (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions