Organelles Flashcards

1
Q

Cells

A

Basic structural units of every organism

2 main types of cells

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2
Q

Prokaryotes

A

NO Nucleus –> Genome in cytoplasm
Smaller Cells

(Mainly bacteria)

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3
Q

Eukaryotes

A

HAS Nucleus
Larger Cells

(Most of the rest of the world: protists, fungi, plants, animals)

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4
Q

Prokaryote Components

A

CELL WALL–> Cell membrane –> Inside of cell:

1) Ribosomes
2) Cytoplasm
3) DNA

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5
Q

Limitations to Cellular Size

A

If cell gets too big, cell membrane wouldn’t be able to meet the demands of its volume

(Because volume increases faster than surface area)

–> Cell membrane must be close to the cytoplasm so that diffusion distances from the membrane to other organelles are smaller

ALL ABOUT EFFICIENCY

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6
Q

Reason for Compartmentalization

A

1) To reduce diffusion distances (make cells more efficient)
2) Separate “incompatible” reactions and their products

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7
Q

Cytosol

A

A semi-fluid, jelly-like substance in which sub-cellular components are suspended (the cellular solvent)

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8
Q

Cytoplasm

A

Refers to the cytosol AND organelles (essentially everything IN the cell)

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9
Q

Plasma Membrane

A

Serves as boundary for every cell to the outside world:

A selective barrier (semi-permeable) that allows the passage of enough materials to service the entire cell

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10
Q

Nucleus

A

A double-membrane organelle that contains most of the genes in a eukaryotic cell (LARGE organelle)

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11
Q

Nuclear Envelope

A

The double membrane of the nucleus (a direct extension of the ER)

–> Confluent with the ER

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12
Q

Nuclear Lamina

A

Mechanically supports the nuclear envelope (made up of an array of filaments) to maintain the shape of the nucleus

–> Is up against the inner nuclear membrane

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13
Q

Nuclear Envelope Structure

A

Outer Membrane –> Perinuclear Space –> Inner Membrane

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14
Q

Chromatin

A

An overarching term referring to all chromosomes

–> All DNA and histones

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15
Q

Histones

A

Proteins that package DNA

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16
Q

Chromosomes

A

Structures that carry genetic info

–> Each contains ONE long DNA strand (molecule), coiled or packaged by histones into the chromosome shape

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17
Q

Nuclear Pores

A

Little “holes” in the nuclear membrane that create a connection between the inside of the nucleus and cytoplasm

–> Allows small molecules to diffuse through (passive transport)

–> Selective about larger molecules: Requires active transport

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18
Q

Nuclear Localization Signal

A

NLS

–> A specific biological marker that gives some molecules access into the nucleus: Needed to get through the pores

“biological passport”

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19
Q

Nucleoplasm

A

KARYOPLASM

The inside of the nucleus

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20
Q

Nucleolus

A

The dark thing in the nucleus: Site of assembly of immature ribosomes

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21
Q

Ribosomes

A

Complexes made up of 2 subunits which are made up of rRNA and proteins

–> Carry out protein synthesis

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22
Q

2 Types of ribosomes

A

Free Ribosomes = Suspended in cytosol

Bounded Ribosomes = Attached to the outside of ER or nucleus

–> Usually produces proteins that are destined for insertion into membranes

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23
Q

Endomembrane System

A

Includes the following:

1) Nuclear envelope
2) The ER
3) Golgi
4) Lysosomes
5) Various vesicles/vacuoles
6) Plasma membrane

24
Q

Vesicles

A

Sacs made of membrane

25
Q

Endomembrane System Connections

A

Connected through one of two ways:
1) Direct physical continuity
2) Transfer of membrane segments as vesicles

26
Q

Endoplasmic Reticulum

A

An extensive network of membranes that accounts for over half of the cell’s membranes

–> Made of membrane tubules and sacs (cisternae)

27
Q

ER Lumen

A

Internal compartment of ER

28
Q

2 Types of ER

A

1) Smooth ER
2) Rough ER

29
Q

Rough ER

A

Has ribosomes attached to the outside and looks more like layered pastry dough

(usually connected to the nucleus)

30
Q

Rough ER Function

A

Protein Synthesis/Modification (mainly secretory proteins)

31
Q

Co-Translational Protein Modification

A

Proteins modified DURING translation

1) Polypeptide chain grows from ribosome (attached to ER)

2) The chain is threaded (inserted) into the ER lumen (N-terminus)

3) Part of protein inside ER begins to be modified while the ribosome is still producing the protein (C-terminus)

32
Q

Glycoproteins

A

Main type of protein ER produces: proteins with a carbohydrate group attached

33
Q

Secretory Proteins

A

To be exported or inserted into membranes

34
Q

Smooth ER

A

Does NOT have ribosomes attached to the outside (looks more like coral)

35
Q

Smooth ER Functions

A

1) Synthesizing lipids
2) Metabolizing Carbs
3) Synthesizing some hormones
4) Detoxify drugs/poisons (by adding -OH, makes it more polar, more soluble)

36
Q

Golgi Body

A

A membranous structure that acts as the center for storage, modification, and transport of ER products

–> Looks like a stack of pancakes a little bit

–> Also has functions in “finishing work” by making some last minute additional modifications to proteins and phospholipids

37
Q

2 Regions of Golgi Body

A

1) Cis-face
2) Trans-face

38
Q

Cis-face

A

Receiving Side (receives incoming vesicle from ER)

39
Q

Trans-face

A

Sending side (sends off vesicle to other parts of the cell)

40
Q

Pathway of ER through Golgi

A

ER –> Transport Vesicle –> Cis-face –> Through Golgi –> Trans-face –> Secretory Vesicle –> Destination

41
Q

Targeting Signals

A

Found on molecules for Golgi to direct to the right location (like a zipcode)

42
Q

Lysosomes

A

Membrane vesicles filled with digestive enzymes (proteases/nucleases) that are used to digest macromolecules

–> Single membrane organelle
–> NOT in plants

43
Q

Lysosome Functions

A

1) Degrade and recycle macromolecules
2) Digest food (in protozoa)
3) Cell Self-destruction

44
Q

Lysosomal Functioning

A

Lysosomes create a microenvironment of pH = 5 (acidic) at which the enzymes function

–> Protects cells as enzymes get deactivated when not in that acidic pH, so if a lysosome breaks, the cell won’t be damaged

45
Q

Central Vacuole

A

The plant substitute for lysosomes

–> A central vesicle surrounded by a special membrane (tonoplast)

46
Q

Tonoplast

A

Membrane of central vacuole

47
Q

Central Vacuole Functions

A

1) Disposal/Recycling
2) Storage of molecules
3) Reduction in cell volume for faster diffusion (as it takes up most of cell volume)

48
Q

Peroxisome

A

A specialized metabolic compartment (bounded by single membrane) which contains enzymes that remove hydrogen atoms from substrates and then attaches them to O2 –> Produces H2O2

49
Q

Peroxisome Functions

A

1) Detoxification of alcohols and other compounds
2) Breaking down fatty acids (to Acetyl CoA: Fueling cell. resp.)

50
Q

Mitochondrion

A

Powerhouse of the cell

–> Double membrane organelle in which cellular respiration occurs to produce most of a cell’s ATP

–> Big organelle: Can see with light microscope

51
Q

Parts of Mitochondria

A

OMM –> IMS –> IMM –> Matrix

52
Q

Mitochondrial Matrix

A

Enclosed by inner membrane

Contains many enzymes as well as the mitochondrial DNA and ribosomes

53
Q

Chloroplast

A

Found in plant cells: A double membrane organelle in which photosynthesis occurs

–> To convert solar energy to chemical energy (sugar)

–> A green plastid

54
Q

Stroma

A

Fluid outside of the thylakoids (contains the chloroplast DNA, ribosomes, and enzymes)

55
Q

Granum

A

Stack of thylakoids

56
Q

Thylakoids

A

Flattened interconnected sacs/discs