Cells Flashcards

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1
Q

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Cells

A
  • 1665 Robert Hooke used a simple miscroscope to look at cork
  • he named the little roomshe observed “cells”
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2
Q

Cell theory

A

1) All organism composed of cells
2) cells are smallest living thing
3) cells arise only from pre-existing cells

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3
Q

Cells today represent

A
  • continious line of descent from the living cells
  • genetic infromation in each cell in multicellular organism is identical
  • multicellular organism can
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4
Q

Cell size is limited

A
  • most cells are relaticely small due to reliance on difussion of substances in and out of cells
  • rate of diffusion affected by surface Area available
  • surface area available
  • temperature
  • concentration gradient
  • distance
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5
Q

how do we examine cell?

A

microscopes

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6
Q

not many cells are

A
  • visible to the naked eye
  • most are less than 50um in diameter
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7
Q

Resolution

A

minimun distance two points can be apart and still be distinguished as two separate points
- objects must be 100 um apart for naked eye to resolve them as 2 objects rather than one

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8
Q

Ligth microscopes

A
  • used magnifying lense with visible light
  • resolve structures that are at least 200 nm apart
  • resolution is limited by the wave length of light
  • ## can magnify cells up yo 1000x
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9
Q

Electron Microscopes

A
  • Use beam of electrons
  • resolve structures that are 0.1 nm apart
  • transmission electron microscopes(TEM)
  • transmit electrons through the material
  • scanning electron microscopes(SEM) beam electrons onto speciemn surface
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10
Q

Basic structural similarities od cells and their componetns

A

1) nucleoid or nucleus where DNA is located

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11
Q

Cytoplasm

A
  • semifluid matrix of organelles and cytosol
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12
Q

Ribosomes

A
  • Synthesize protein
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13
Q

Plasma mebrane

A
  • Phospholipid bilayer
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14
Q

Prokaryotic cells

A
  • Simplest organism
  • lack membrane-bound organelles
  • DNA is present in the nucleoid
  • cell wall outside of plasma membrane (not membrane-bound organelles)
  • ## two domains of prokaryotes
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15
Q

Bacteria cell walls

A
  • most bacterial cells are encased by a strong cell wall
  • composed of peptidoglycan
  • cell walla of plants and fungu are different (what are they composed of? review from earlier)
  • protect the cell, maintain its shape, and orevent excessive uptake or loss of water
  • susceptibility of bacteria to antibiotics often depedns on the structure od their cell walls
  • archea lack pepti
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16
Q

Flagella

A
  • Represent in some prokaryotic cells
  • may have one or more or none
  • used for locomotion
  • rotary motion propels the cell
17
Q

Eukaryotic cells

A

-

18
Q

Nucleus

A
  • Repository of genetic information
  • most eukaryotic cells possess a single nucleus
  • nucleolus-region where ribosomal RNA synthesis takes place
  • In eukaryotes, the DNA is divided into multiple linear chromosomes
  • chromatin is DNA plus protein
19
Q

Nuclear envelope

A
  • 2 phospholipid bilayer (4 totsl phospholipid sheets)
  • nuclear pores-control passage of molecules in and out
20
Q

Ribosomes

A
  • cell’s protein synthhesis machinery
  • found in all cell types in all 3 domains
  • ribosomal RNA (rRNA)- protein complex
  • protein synthesis also requires messenger RNA (mRNA) and transfer RNA (tRNA)
  • ## Ribosomes may be free in cytoplasm or associated with internal membranes
21
Q

Endomembrane system

A
  • series of membranes throughout the cytoplasm
  • divides cell into compartments where different cellular function
  • fundamental distinction between eukaryotes and prokaryotes
22
Q

Endoplasmic reticulum-
Rough endoplasmic reticulum

A
  • attachment of ribosomes to the membrane gives a rough appearance
  • synthesis of proteins to be secreted, sent to lysosomes or plasma membrane
23
Q

smooth enfoplasmic reticulum

A
  • Relatively few bound ribosomes
  • variety of functions-lipids synthesis, store Ca2+, detoxification
  • Ratio of RER to SER depends on cell’s function
  • celll that carry out extensive lipid synthesis
    (testes, intestines, brain) = more SER
    Cells that synthesize proteins that are secreted (endocrine cells)= more RER
24
Q

Golgi apparatus

A
  • function in packing and distribution of molecules
  • flattened stacks of interconnected membranes (golgi bodies)
  • has cis and trans face
  • vesicles transport molecules to destination:
  • other organelles
  • plasma membrane
25
Q

Protein transport through the endomembrane system

A

1) vesicle contians proteins buds form the rough ER diffise, though the

26
Q

Lysosomes

A

-membrane-bounded digestive vesicles
low pH enviroment (4.5-5.0)
- arise from golgi apparatus
- enzymes catalyze breakdown of macromolecules
- resulting monomers can be used for subsequence de novo synthesis reactions
- destroy cells or foreign matter that the cell has engulfed by phagocytosis

27
Q

peroxisomes

A

-membrane bound vesicle
- contain enzymes involved in the oxidation (breakdown) of fatty acids
- Contains enzyme to breakdown toxins such as metabolic waste products, alcohol and drgus
- hydrogen peroxide produced as by-product from cellular reaction reaction- rendered harmless by catalase

28
Q

Vacuoles

A
  • membrane-bounded structures in plants
  • various functions depending on the cell type
  • there are 3 different types of vacuoles: central vacuole in plants cells (help maintain rigidity)
  • contractile vacuole of some fungi and proptists
  • storage vacuoles
29
Q

Mitochondria

A
  • Found in al typesof eukaryotic cells
  • have their own DNA (genome)!
  • Bounded by membrane
  • intermembrane space
  • inner membrane has cristae
  • matrix is the most internal
  • Protains that carry out oxidative metabolism are located
  • on the surface of the inner membrane
  • and embedded within the inner membrane