Chapter 4 - Cell Structure Flashcards

1
Q

Scientific units

A
Cm - 1m = 100cm
Mm - 1m = 1000mm
Um - 1m = 1,000,000um
Nm - 1m = 1,000,000,000nm
A - 1m = 10,000,000,000A
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2
Q

Fathers of cell biology

A

Schleiden + Schwann: proposed cell theory. Schleiden= plant cell
Schwann= animal cell

Hooke+Oken: hooke discovered and named cells (cork)
Oken: believed that all living things are made of cells

Virchow: contributed 3rd point in cell theory ( cells divide)

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3
Q

Cell theory

A

1) all organisms are made of 1 or more cells. Metabolism+heredity occur inside cells
2) cells are the smallest living things
3) cells arise only from division of previously existing cells.

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4
Q

Magnification

A

How many times bigger than life the object viewed appears

Combination of power of ocular+objective lens

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5
Q

Resolution

A

The ability to distinguish between 2 objects which are separate

Something that changes with each type of microscope used

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6
Q

Light microscope

A

Light passes through specimen+lenses

Lenses magnify and focus image

Light-condenser-slide-magnifier-ocular lens

Light shines from bottom

Resolution= approx. 0.2um or 200mm

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6
Q

Light microscope

Tissue prep

A

1) kill specimen
2) fix it (preserve with chemicals)
3) embed in wax or plastic
4) slice with microtome
5) stain it

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7
Q

Electron microscope

A

Electrons pass through or to specimen

Wavelength is shorter than light microscope - shorter wavelength increases resolution

Electron source on top of microscope

Uses magnets as lenses

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8
Q

Scanning electron microscope (SEM)

A

Specimen @bottom

Electrons go through 3 sets of magnetic lenses-through the coil-bounces off specimen-image read by detector-image goes through black box and to viewing screen.

Resolution= 10nm - creates 3D image

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9
Q

Transmission electron microscope (TEM)

A

Specimen goes after 1st electromagnetic lens-acts as condenser

Electrons pass to objective lens+to the projective lens

Viewing screen is @ bottom where image can be viewed

Resolution: 0.2nm - 1000x better than light microscope

Much larger than light and requires a vacuum

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10
Q

TEM

Tissue prep

A

1) kill specimen
2) dehydrate specimen
3) slice + put in plastic
4) stain with heavy metals

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11
Q

Prokaryotic cells

A
Before nucleus
Small,simple,unicellular 
No membrane bound organelles
Live anywhere eukaryotes live,but can live many place eukaryotes can't 
Most abundant 
Oldest
No nucleus
Nucleoid region (DNA)
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12
Q

Eukaryotic cells

A
After nucleus
Larger than prokaryote
Complex-specialized cells
Some uni but most multicellular 
Have membrane bound organelles 
Has nucleus
Complex DNA (in nucleus)
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13
Q

Prokaryotes

Bacteria

Structures

A
Ribosomes
Plasmid
Flagellum
Cytoplasm/protoplasm
No nucleus/nucleoid region instead
Little structure 
Rod/spherically shaped
Plasma membrane
Pili
Cell wall (peptidoglycan)
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14
Q

Bacteria

Gram staining (+/-)

A

Gram + bacteria: thick cell wall-crystal violet stain makes cell wall purple

Gram - bacteria: thin cell wall-crystal violet does not stain-use another stain which turns it pink

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15
Q

Cytoplasm/protoplasm

A

Semi fluid matrix
Fills interior of cell
Contains all sugars, amino acids, and proteins cell needs
Jello-like consistency

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16
Q

Pilus

A

Hair-like extensions

Allows cell to transfer genetic materials from one cell to another

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17
Q

Nucleoid region

A

The area near the centre of the cell that contains most of the genetic material DNA

In cells with no nucleus

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18
Q

Ribosomes

A

Circular shape
Organelles that carry out protein synthesis
Made of 2 subunits that are made of rRNA and proteins
On RER
Subunits only join to make proteins

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19
Q

Plasmid

A

A small fragment of circular double stranded DNA that replicates on its own.

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20
Q

Flagellum

A
Long thread-like structures
On the surface of cell
Used for movement
Rotates like tails' foxy tails 
Doesn't whip back and forth
21
Q

Capsule

A

A gelatinous layer surrounding the cell wall.

Prokaryotic cells

22
Q

Cell wall

A

Bacteria is made of peptidoglycan
Plants= cellulose
Fungi=chitin
Primary cell wall-outermost wall
Middle lamella-glues plant cells together
Secondary cell wall- when cell matures inside primary cell wall

23
Q

Plasma membrane

A
Separates cell from outside environment 
Surrounds the cytoplasm.
Consists of a single phospholipid bilayer 
Proteins embedded in it
Selectively permeable 
Cholesterol gives flexibility 
Receptor/transmembrane sites
Interior protein network
Cell surface markers
24
Q

Prokaryotes

2 kingdoms

A

Bacteria

Archaea

25
Q

Archaea

A

No peptidoglycan in cell wall

Less flexible but have membranes that allow them to live in extreme environments.

Can’t adapt well

Has good thermal stability

Membrane has bilayer

Pseudomuran?

26
Q

Bacteria in a light microscope

4 classifications

A

1) gram stain
2) flagella
3) cell shape
4) aggregations

27
Q

Identifying cell shape

A

Circle - coccus (sing.) cocci (pl.)

Oval - bacillus (sing.) bacilli (pl.)

Comma - vibrios (pl.)

Spiral - spirillium (sing.) spirilla (pl.)

28
Q

Aggregation

A

One cell - shape name
2 cells - diplo+shape name
Group of cells - stephalo+shape name
Strand of cells - strepto+shape name

29
Q

Origin of eukaryotic cells

2 reasons why prokaryotes existed before eukaryotes

A

1) prokaryotes date 2 billion yrs. before eukaryotes -fossil record
2) complexity of eukaryotes compared to prokaryotes - first thing that changed was the separation of DNA functions and protein building (nucleus)

30
Q

Endosymbiosis theory

A

Large prokaryote underwent unfolding
Small prokaryotes engulfed by large prokaryote without being digested

Aerobic=mitochondria
Photosynthetic=chloroplasts

Lead to protoeukaryotic cell - transition cell
Small cells became endosymbionts - both benefits

31
Q

Nucleus

A
Controls all cell activities 
Contains DNA,RNA+proteins
Largest organelle 
Spherical 
Some have cytoplasmic skeleton to hold it in place.
Nucleoplasm-cytoplasm inside nucleus
32
Q

Chromatin

A

A complex structure of protein organized chromosomes

33
Q

Nucleolus

A

Region of nucleus where intensive synthesis of ribosomal RNA takes place.

34
Q

Nuclear membrane

A

2 phospholipid membranes
Nuclear pores - allows ions+small molecules to diffuse between nucleus+rest of the cell
Outer membrane connects to ER

35
Q

Mitochondria

A

Oval shaped
Energy metabolism
Double membrane
Own DNA+ribosomes
Both plant+animal cells
Does own cell division
Thought to have arisen from endosymbiosis.
Cristae (christa sing.) - Inner folded membrane. Has proteins that carry out oxidative metabolism(making ATP)
Matrix-inside inner membrane
Intermembrane space- between the 2 membranes.

36
Q

Chloroplasts

A

Oval shape
Only in plants
Thought to have arisen by endosymbiosis
Make their own food
Energy metabolism
Double membrane
Own DNA/ribosomes
Contains chlorophyll which makes plants green
Grana (granum sing.)-stacked closed compartments inside inner membrane.
Grana have thylakoids-disk shaped structures.
On surface of thylakoids-light capturing pigments -photosynthesis-chlorophyll.
Stroma- fluid matrix surrounding thylakoids.

37
Q

Endosymbiosis

A

When a free-living cell is eaten by another cell but not digested.

38
Q

Vacuole

A
Oval shaped
Only in plants
Tonoplast membrane 
Stores useful molecules and wastes
Plant cells grow by expanding the vacuole
Contractile vacuoles - can pump water
39
Q

Tonoplast

A

The membrane surrounding a vacuole
Contains channels - lets water in and out
Maintains tonicity/osmotic balance

40
Q

Vesicles

A

Circular shape
Membrane bounded sac
Various substances are transported or stored.

41
Q

Microbodies

A
Circular shape
One membrane
Contains a variety of enzymes
Peroxisomes 
Glyoxysomes
42
Q

Peroxisomes

A

A microbody that breaks down hydrogen peroxide by catalase

43
Q

Glyoxysomes

A

A microbody that contains enzymes that convert fat into carbohydrates.
Plants

44
Q

Lysosomes

A
Digestive vesicles
Come from Golgi apparatus 
Contains enzymes that catalyze the break down of proteins, lipids,carbohydrates and nucleic acids
Recycle old organelles 
Eliminates engulfed cells
45
Q

Plastids

A

Circular shape
In plants
Site of photosynthesis and starch storage

46
Q

Leukoplasts

A

A colourless plastid in which starch grains are stored; usually found in cells not exposed to light.(root cells)

47
Q

Endoplasmic reticulum

ER

A

Phospholipid bilayer embedded with proteins
Provides surface for protein and lipid synthesis
Rough (RER)
Smooth(SER)

48
Q

Rough endoplasmic reticulum

RER

A

Many ribosomes imbedded
Proteins synthesized on the surface are exported from the cell,sent to lysosomes or vacuoles,or embedded in plasma membrane
Proteins can be modified by adding short chain carbohydrates majoring glycoproteins.
Proteins enter the cisternal space (facing the nucleus)

49
Q

Smooth endoplasmic reticulum

SER

A

The membrane contains many embedded enzymes.
The enzymes synthesize carbohydrates and lipids.
Steroid hormones are also synthesized
Stores intracellular calcium.
Modifies foreign substances to make them less toxic