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BIOB 260 > Cells > Flashcards

Cells Flashcards

bc I hate myself apparently

1
Q

Anatomy of a cell

A

don’t think we have to be able to draw this

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2
Q

Morphology
(types)

A

Prokaryotes
no membrane-bound nucleus
Eukaryotes
membrane-bound nucleus

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3
Q

Grouping Cells
(phylogeny)

A

phylogeny = evolutionary history
Bacteria—prokaryotic
Archaea—prokaryotic
Eukarya—eukaryotic

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4
Q

Bacteria
(Basic Structure)

A

0.5–5.0 um (1/10th the size of Eukaryotic cells)
One circular chromosome in the nucleoid region of the
cell
The chromosome contains one long strand of
DNA a few supportive proteins
The DNA double helix is “supercoiled”
no membrane

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5
Q

Eukaryotic Cell
(Basics)

A

10-50x larger than Prokaryotes
made up of membrane bound organelles

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6
Q

Cytosol vs cytoplasm

A

cytosol = fluid
cytoplasm=within cell membrane

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7
Q

Advantages of compartmentalization (2)

A
  1. Separate incompatible chemical
    reactions
  2. Increase the efficiency of chemical
    reactions
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8
Q

Nuclear Envelope

A

Double membrane
Nuclear Pore Complex :
Acts like a gate
What comes in?
Nucleosides, proteins
What goes out?
mRNA, rRNA
* rRNA- made in nucleolus *
Small and large subunits

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9
Q

Pore
(in cells)

A

openings Inside surface
linked to fibrous proteins = nuclear lamina

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10
Q

Nucleolus

A

rRNA synthesis - ribosomal
subunit assembly

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11
Q

Rough Endoplasmic Reticulum (ER)

A

membrane-bound tubes and sacs with attached ribosomes
* interior is called the lumen
continuous with the nuclear envelope
Synthesis of proteins destined for the membrane or secretion

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12
Q

Ribosomes

A

Protein “Factory”
non-membranous
large (60S) and small (40S) subunits
made of rRNA and proteins

  • Can be free in the cytosol:
    synthesis of proteins that remain in the cytoplasm
    or go into the nucleus or mitochondria
  • When attached to rough ER
    synthesis of integral membrane proteins and
    secreted proteins
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13
Q

Smooth Endoplasmic Reticulum (ER)

A

Synthesis (and break-down) of lipids and storage of Ca2+

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14
Q

Golgi Apparatus

A

stacked flat membranous sacs called cisternae

cis surface is closest to the nucleus
trans surface is oriented toward the plasma membrane

The cisternae travel from cis to trans and mature as they move to the trans end –> enzymes recycle during this (go backwards)

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15
Q

Golgi Apparatus
(Function)

A

Protein, Carbohydrate, Lipid Processing

  • cis side receives products from the rough ER (vesicles)
    Processes, sorts, and ships the proteins synthesized in the rough ER
  • trans side ships them out to other organelles
    or the cell surface (vesicles)
    Membranous vesicles carry materials to and from the Golgi
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16
Q

The path of proteins

A

ER —> cis Golgi —> trans Golgi —> plasma membrane, organelles or secreted

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17
Q

Lysosome

A

Recycle
Contain digestive enzymes (pH 5.0)- acid hydrolases
* Maintained by proton pumps (active transport)
* Found only in animal cells *

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18
Q

Lysosome
(Function)

A

digest macromolecules
process waste

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19
Q

Do hydrolysis or condensation reactions
occur in the lysosome?

A

Hydrolysis

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20
Q

Acid Hydrolases Path
(5 steps)

A
  1. Transcription of acid hydrolase gene in the
    nucleus into mRNA
  2. mRNA travels through nuclear pore into
    rough ER.
  3. In the rough ER the mRNA is translated
    into proteins via the ribosomes.
  4. A vesicle containing the enzyme travels to
    the cis region of the golgi apparatus for
    further packaging.
  5. A vesicle containing the packaged acid
    hydrolase enzyme buds off the trans region
    of the golgi and incorporates with
    lysosomes.
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21
Q

Peroxisomes

A

Detox Center

originate as buds from the
ER (single membrane)
Reduction-oxidation reactions
* Special Enzymes: Oxidase and Catalase

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22
Q

Oxidase

A

neutralizes free radicals
(unpaired electrons,O2-) to H 2 O2.
Detox alcohol and formaldehyde

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23
Q

Catalase

A

removes hydrogen peroxide

24
Q

Mitochondria

A

Energy !
two membranes
inner folded sac-like cristae
Inside the cristae is the mitochondrial matrix
Its own circular DNA (37 genes) and ribosomes
* 50-1,000,000 mitochondria per cell *
Enzymes for ATP production embedded in the membranes of the cristae or soluble in the matrix

25
Q

Chloroplasts

A

Make CHO from Sunlight
* in most plant and algal cells *
Have a double membrane
Circular DNA and small ribosomes
thylakoids are flattened membrane-bound structures
Fluid outside the thylakoids is stroma

26
Q

Photosynthesis

A

Pigments and enzymes in the thylakoid membranes convert light energy to chemical energy
Enzymes in the stroma use this chemical energy to produce sugars
6CO2 + 6H2O → C6H12O6 + 6O2

27
Q

Vacuoles

A

Storage
large, membrane-bound structures in plants and fungi
* possibly : digestive enzymes *
Storage of water and/or ions (maintain cell volume)

Noxious compounds to protect leaves and stems from being eaten (tannins, nicotine, morphine, caffeine)

28
Q

Cytoskeleton

A

Movement and Structure
* composed of protein fibers *
cell shape and structural stability
organizes :
* All of the organelles
* Aids cell movement
* Transport of materials within the cell

29
Q

Review Of Organelle Slide
(little brain break <3)

A
30
Q

Nuclear Pore

A

Selective
Nuclear Localization Signal
17 amino acid stretch
* contains basic amino acids *

Recognized by importin- protein
Exportin- protein : signal for proteins that leave the nucleus

31
Q

Brain Break

A
32
Q

~ Brain Break~

A

u got this !!

33
Q

Protein Tagging

A

Green fluorescent protein (GFP) !
Use the DNA sequence
Add to N terminus or C terminus
GFP is small
Shine blue light and it fluoresces green
Because of its unique 3D shape!

34
Q

Protein Importation

A

Proteins that are imported into the nucleus are made on cytoplasmic ribosomes
* Most proteins in mitochondria, chloroplasts, and
peroxisomes:
-synthesized on cytoplasmic ribosomes
-contain signal sequences that target them to the
appropriate organelles *

35
Q

Endomembrane System
(Function)

A

Manufacture, Ship, and Recycle
Secreted proteins, membrane proteins, proteins contained in some organelles
Ex: hydrolases that need to be placed in lysosomes

36
Q

Secretion Pathway

A

1- mRNA (nuclear pore)
2- Rough ER (lumen)
3- Vesicle
4- Cis Golgi (vesicle)
5- Trans Golgi (vesicle)
6-Plasma membrane (vesicle)

37
Q

Free Ribosome vs. ER Ribosomes

A

Free - in cytosol
proteins go to:
nucleus, mitochondria, chloroplasts, peroxisomes
ER - Bound
proteins go to:
plasma membrane, secretory vesicles, lysosomes

38
Q

Transfer to Golgi

A

Proteins are transported in vesicles.

Vesicles bud off from ER and join with the cis end of the Golgi

39
Q

Leaving the Golgi

A

vesicles leaving the Golgi have molecular labels.
Ex: hydrolytic enzymes for lysosomes tagged with mannose-6-phosphate

40
Q

No question just Lysosome Review Slide

A
41
Q

Microtubules

A

Composed of micro + intermediate filaments
Actin subunit
Fibrinous Subunit

42
Q

Actin

A

most prevalent protein in the cell
non-polar covalent bonds
G-actin- single globular subunit
F-actin- filamentous actin-multiple subunits

43
Q

F-Actin

A

polarity: plus and minus ends (no net charge)
Parallel
The plus end grows faster than the minus end
Actin binding proteins regulate the length, longevity, stability

44
Q

Actin Proteins

A

Thymosin- binds G-actin subunits and prevents assembly
Profilin- binds subunits and speeds elongation
Arp2/3- nucleates (starts) actin polymerization

45
Q

Actin Treadmill

A

G-Actin monomers coming and going at an equal rate
Arp23 allows branching of fibers
proteins regulate speed

46
Q

Actin Polymerization

A

Cell Movement
When : cut (white blood cells), cancerous, developing
Lamellipodia + Filopodia
* G-actin polymerizes into F-actin determines direction of cell movement *

47
Q

Lamellipodia

A

Wave-like front
leading edge of cell
Directs movement

48
Q

Filopodia

A

Small finger-like projections
Ex: Arp23

49
Q

Myosin

A

Binds Actin
binds and hydrolyses ATP –> ADP (shape change)

  • Shape change causes myosin head to contract and pull
    itself along actin *
50
Q

Actin Interactions with Myosin

A

Movement
Muscle contraction
Myosin (thick filaments) bind to and walk along F-
actin
filaments (thin filaments)
Cytokinesis
Shrinking contractile ring of actin-myosin filaments
Cytoplasmic Streaming

51
Q

Tropomyosin and troponin

A

Myosin proteins ?
stabilizes and stiffen actin filaments
prevent myosin head from interacting with actin

  • When Ca+2 is present it binds
    troponin-tropomyosin allowing
    myosin head to bind *
52
Q

Microtubules
(Structure)

A

Large, hollow tubes made of tubulin dimers
Two proteins: α-tubulin + β-tubulin
Bound together by non-covalent bonds
Have polarity
Usually grow at their plus ends

53
Q

Microtubules
(Functions)

A

Tracks within cell
Move organelles and vesicles
Motile Cilia and Flagella
Mitosis- bind chromosomes

54
Q

Centrosome

A

two perpendicular bundles of short microtubules (centrioles)

55
Q

Microtubule Motor Proteins

A

Kinesin: motor protein towards the + end
Dynein: motor protein moves toward the – end

56
Q

Cytoskeleton
(Overview)

A
  1. Mobile fibroblast
    Dynamic actin assembling lamellipodia and filopodia
  2. Cell division of fibroblast
    Actin reorganizes to give cell a rounded shape
    Microtubules bind chromosomes
  3. After chromosome separation
    Actin filaments form a contractile ring (myosin)
  4. Fibroblast daughter cells can “crawl” their individual way
57
Q

Intermediate filaments
(Function)

A

Defined by size, not composition
Ex : keratin, lamin
Many types, each made of a different protein
Are not involved in movement (no motor proteins)
Do not have polarity (no + or – ends)
Project from the nucleus and from the plasma membrane
Shape the cell surface (structural support)
Hold the nucleus in place

BIOB 260 (5 decks)

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