Ch 2: Cells Flashcards

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1
Q

What is life?

A
  1. Response to the environment
  2. Exchange of materials with the environment
  3. Metabolism
  4. Growth
  5. Reproduction

Cell is first fundamental sign of life.

Virus is not alive

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2
Q

Prokaryotic cells

A
  • No true nucleus
  • 1 to 10 µm
  • ex: bacteria
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3
Q

Eukaryotic cells

A
  • Have a true nucleus
  • 10 to 100 µm (1/100 to 1/10 mm)
  • almost all other cells that are not bacteria
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4
Q

Unicellular

A
  • Each cell carries out all life processes
  • Usually found in clusters
  • Bacteria are unicellular
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5
Q

Multicellular

A

Made up of many cells, with different cells specialized to perform different functions

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6
Q

Why are cells so small?

A

Cells are small because they require a high surface to volume ratio to exchange materials with their environment.

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7
Q

Bacterial cells

A
  • Prokaryotic
  • no true nucleus
  • no endoplasmic reticulum
  • no Golgi apparatus
  • no mitochondria
  • no chloroplasts
  • no vesicles or vacuoles
  • no centrosome
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8
Q

Bacterial cell anatomy: Cytosol

A
  • Mixture of enzymes and many other molecules in water.
  • Many chemical reactions take place in the cytosol.
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9
Q

Bacterial cell anatomy: Flagellum

A
  • Hair-like
  • Attaches at plasma
  • Rotates to provide mobility
  • Not all bacteria have it
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10
Q

Bacterial cell anatomy: Thylakoid

A

Provides a membrane for photosynthesis

Not all bacteria have this

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11
Q

Bacterial cell anatomy: Capsule

A
  • Not all bacteria have this
  • Thick, sticky, gooey layer
  • Protects the cell from attack or dehydration
  • Allows some cells to stick together
  • When bacteria with a capsule infect you, your immune system doesn’t recognize them/kill them.
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12
Q

Bacterial cell anatomy: Plasmid

A
  • Not all bacterial cells have this
  • Accessory genetic information
  • Bacteria can trade these
  • Scientists can use it to add extra genes for our purposes
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13
Q

Bacterial cell anatomy: Cell wall

A
  • NOT a fluid like the plasma membrane
  • Relatively rigid (gives the cell its shape)
  • Prevents it from bursting
  • Porous
  • Most bacteria (not all) have this
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14
Q

Bacterial cell anatomy: Plasma Membrane

A
  • AKA cell membrane
  • Boundary between cell and environment.
  • Controls movement of material in and out (exchange)
  • Made of a phospholipid bilayer
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15
Q

Plasma membrane: Phospholipid bilayer

A
  • Made of lipid molecules that have a polar head and non-polar tails.
  • In water, the tails go in towards the center and the heads form two layers surrounding the tails because the heads like water but not the tails (semi-permeable)
  • This bilayer is actually a fluid (not solid)
  • The non-polar layer makes it relatively non-permeable to polar molecules.
  • The non-polar molecules pass through easily (CO2 , O2 , lipids, …). They diffuse through freely.
  • Some small polar molecules can actually sneak in, but very slowly.
  • Larger polar molecules (ex: glucose) and ions diffuse through hardly at all, but there are some proteins embedded in the bilayer that will let some of the important stuff in.
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16
Q

Facilitated Diffusion (plasma membrane)

A
  1. Channel protein: Very specific about what it lets in. No control over in-out direction. Aquaporins (water channels)
  2. Gated channel proteins: Gates open or close depending on what the cell needs (or other various events)
  3. Carrier protein: only allows in a specific, but larger molecule.
  • All 3 of these help with facilitated diffusion or passive transport (diffusion to areas of smaller concentration)
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17
Q

Active transport protein

A
  • Also for transport in or out of the cell, but not by diffusion (it can bring something in even in concentration is higher inside)
  • The cell provides energy to this protein which transports specific molecules in or out of the cell
18
Q

Animal cells

A
  • no cell wall
  • no plasmodesmata
  • no chloroplasts
  • no central vacuole
  • DNA is not in a loop like in prokaryotic cells
19
Q

Eukaryotic Cell Anatomy (Animal)

A
20
Q

Animal Cell Anatomy

Better View of the Cytoskeleton

A
  • Centrosome: Contains centrioles. With pair of centrioles, the centrosome organizes the cytoskeleton
  • Cytoskeleton: Gives the cell its shape, allows cell to change its shape, helps with intracellular transport
21
Q

Eukaryotic Cell Anatomy (Animal)

Plasma Membrane

A
  • Phospholipid bilayer
  • Tight junction protein: helps cells stick together
  • Extracellular matrix: strengthens tissues, helps cells to react to the environment (with glycoproteins like glycogen)
  • Cholesterol: helps maintain membrane fluidity. Non-polar
  • Protein receptor: allows cells to respond to only specific chemicals
22
Q

Eukaryotic Cell Anatomy

Animal

Cytosol

A
  • Synthesis of proteins that need to be packaged
23
Q

Eukaryotic Cell Anatomy

Animal

Cilium

A
  • Coordinated beating to provide mobility
24
Q

Eukaryotic Cell Anatomy

Animal

Flagellum

A
  • Unlike in prokaryotic cells, these whip instead of rotate to provide mobility
25
Q

Eukaryotic Cell Anatomy MITOCHONDRION (Animal)

A
  • Generates ATP for the cell
  • Have several features that are similar to a prokaryotic cell
  1. Outer Membrane: similar to the plasma membrane
  2. Inner Membrane: similar to a prokaryotic plasma membrane
  3. Loop of DNA
  4. Ribosomes: Similar to prokaryotic ribosomes
  5. Matrix: Fluid, similar to cytosol
26
Q

Eukaryotic Cell Anatomy

Animal

Nucleus

A
  • Nucleus contains the nucleolus, chromatin and nuclear envelope
  • Definining feature of the eukaryotic cell
  1. Nucleolus: Site of assembly of ribosomes
  2. Nuclear envelope: Double membrane
  3. Chromatin: Substance holding most of the genetic information. Made of several diffuse chromosomes (each made of one double-stranded DNA molecule with associated proteins)
27
Q

Eukaryotic Cell Anatomy

Animal

Smooth endoplasmic reticulum

A
  • Synthesis of lipids
  • Destruction of drugs and toxins (we have many in our liver)
28
Q

Eukaryotic Cell Anatomy

Animal

Rough Endoplasmic Reticulum

A
  • Synthesis of proteins that need to be packaged (i.e. needed in the blood to signal, but not needed in the cell. ex: insulin)
  • Looks rough under a microscope because it’s covered in ribosomes
29
Q

Eukaryotic Cell Anatomy

Animal

Ribosomes

A
  • Protein synthesis
30
Q

Eukaryotic Cell Anatomy

Animal

Vacuole

A
  • Larger membrane sack of material
  • Several types: Lysosome (vacuole of digestive enzymes
31
Q

Eukaryotic Cell Anatomy

Animal

Vesicle

A
  • Small membrane sack of material
  • Small packages that pinched off the rough ER
  • Composed of a phospholipid biliayer
  • Package will go join the Golgi Apparatus
32
Q

Eukaryotic Cell Anatomy

Animal

Golgi Apparatus

A
  • Phospholipid bilayer
  • Package, modify and sort proteins from Rought E.R.
33
Q

Plant cells

A
  • no centrosome
  • no lysosomes
  • cell wall: cellulose. Cell walls are NOT present in animal cells.
  • Cytoskeleton, but no centrosome. The nuclear envelope organises part of the cytoskeleton.
  • Chloroplasts (site of photosynthesis in plants)
  • Large central vacuole (storage, turgor (stiffness caused by water pressure)). Animal cells tend to have many small ones instead.
  • Plasmodesmata: channel that allows connection between cells. Allows cytosol and other material to move from cell to cell.
34
Q

Plant cells: Chloroplast

A
  • Contains a loop of DNA
  • Thylakoid: provides a membrane for photosynthesis
  • Stroma
  • Inner membrane (phospholipid bilayer)
  • Outer membrane
  • Ribosome
35
Q

Fungal cells

A
  • eukaryotic
  • cell wall: chitin
  • pores between cells
  • no plasmodesmata
  • no centrosome
  • no chloroplasts
36
Q

Cytosis

A

Transport via folding of a membrane

  1. Endocytosis: Entering the cell by cytosis
  2. Exocytosis: Exiting the cell by cytosis
37
Q

What is different about a Bacterial Cell?

A
  1. no true nucleus
  2. no endoplasmic reticulum
  3. no golgi apparatus
  4. no mitochondria
  5. no chloroplasts
  6. no vesicles or vacuoles
  7. (basically no organelles)
  8. no centrosome
38
Q

What is different about an Animal Cell?

A
  1. No cell walls
  2. No plasmodesmata
  3. No chloroplasts
  4. No central vacuole (only a bunch of little ones)
39
Q

What is different about plant cells?

A
  1. No centrosome
  2. No lysosomes
  3. Cell wall is made of cellulose (chemically different than the wall of a bacteria. Cellulose = polusaccharide
40
Q

What is different about Fungal Cells?

A
  1. Eukaryotic
  2. Cell wall: chitin
  3. No plasmodesmata
  4. Pores between cells (large)
  5. No centrosome
  6. No chloroplasts