chapter 3 Flashcards

1
Q

what is the cell theroy

A

All organisms composed of cells and cell products

Cell is the simplest structural and functional unit of life

An organism’s structure and functions are due to activities of cells

Cells come only from preexisting cells

Cells of all species exhibit biochemical similarities

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2
Q

what is cytology

A

scientific study of cells

Began when Robert Hooke coined the word cellulae to describe empty cell walls of cork in 17th century

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3
Q

what did louis Pasteur demonstrate

A

cells arise only from other cells = refuted the spontaneous generation theory

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4
Q

how many tupes of cells in human body

A

200 types with varied shapes

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5
Q

what are the 9 common cel shapes

A

squamous- thin flat scaly…. esophagus, epidermis

cuboidal- squarish…. liver cells

columnar- taller than wide….. stomach lining/ intestines

polygonal- irregularly angular shapes, multiple sides

stellate- star like…. nerve cell

spheroid to ovoid- round to oval…. egg/wbc

discoid- disc shaped…. RBC

fusiform- thick in middle, tapered ends

fibrous- thread like… muscle cells

cells measured in micrometers

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6
Q

plasma membrane

A

Surrounds cell, defines boundaries

Made of proteins and lipids

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7
Q

cytoplasm

A

everything inside of cell

Organelles
Cytoskeleton
Inclusions (stored or foreign particles)
Cytosol (intracellular fluid, ICF)

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8
Q

extracellular fluid (ECF)

A

Fluid outside of cells includes tissue (interstitial) fluid

  • tissue fluid (intersitial fluid)
  • blood, plasma, lymph and cerebral spinal fluid
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9
Q

what is the function of the plasma membrane

A

Defines cell boundaries
Governs interactions with other cells
Controls passage of materials in and out of cell

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10
Q

what is the structure of the plasma membrane

A

98% membrane molecules are lipids

  • phospholipids (75% lipids)
  • cholesterol (20%)
  • glycolipids (5%)

2% protein membrane proteins

  • integral proteins
  • peripheral proteis
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11
Q

describe phopholipids

A

75% of membrane lipids are phospholipids
Hydrophilic phosphate heads face water on each side of membrane
Hydrophobic tails—are directed toward the center, avoiding water
Drift laterally, keeping membrane fluid

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12
Q

describe cholestrol

A

20% of the membrane lipids

Holds phospholipids still and can stiffen membrane

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13
Q

describe glycolipids

A

5% of the membrane lipids
Phospholipids with short carbohydrate chains on extracellular face
Contributes to glycocalyx—carbohydrate coating on cell surface

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14
Q

describe integral proteins

A

penetrate membrane

Transmembrane proteins pass completely through

Hydrophilic regions contact cytoplasm, extracellular fluid
Hydrophobic regions pass through lipid of the membrane

Some drift in membrane; others are anchored to cytoskeleton

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15
Q

describe peripheral proteins

A

Adhere to one face of the membrane (do not penetrate it)

Usually tethered to the cytoskeleton

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16
Q

what are the functions of membrane proteins

A

receptors- binds to chem messengers (hormones) sent from other cells

enzymes - breaks down chem messengers

channels - constantly open allows solutes to pass

gated channels - opens/closes to allow certain solutes through

cell identity markers- distinguishes body own cell from foreign cell

cell adhesion molecule- binds one cell to another

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17
Q

what did theodor schwann conclude to contribute to cell theory

what did hooke contribute

A

all animals made of cells

coined word cellulae starting cytology

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18
Q

describe glycocalyx (aka its composition)

A

fuzzy coat external to plasma membrane of carbohydrate complexes

carbohydrate complexes =
-glycoproteins/glycolipids

unique in everyone but identical twins

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19
Q

what is the function of the glycocalyx

A

protection

immunity to infection

defense against cancer

transplant compatibility

cell adhesion

fertilization

embryonic development

20
Q

what are the cellular extensions

A

microvilli

flagella

cilia

21
Q

describe structure/function of microvili

A

extension of membrane (shortest of the three)

best developed in cells meant for absorption (intestines)

function is to increase surface size/ aid in absorption

22
Q

describe the structure and function of flagella

A

in humans is the tail of the sperm (only ffunctional one)

for movement: undulating snakelike corkscrew mvmts

23
Q

describe the structure and function of cilia

A

long hairlike processes

nonmotile cilium is found on nearly every cell

functions

  • ateena for monitoring nearby conditions
  • balance (inner ear)
  • light detection (retina)

there are multiple nonmotile cilia

  • found sensory cells of nose
  • respiratory tract
  • uterine tubes
  • ventricles of brain
  • ducts of testes

beat in waves to sweep material across surface in one direction

24
Q

what is the cytoskeleton and what is it composed of

A

network of protein filaments and cylinders

composed of: microfilaments. intermediate fibers, microtubiles

25
what is the function of the cytoskeleton
Determines cell shape Supports structure Organizes cell contents Directs movement of materials within cell Contributes to movements of the cell as a whole
26
describe microfilaments
thinnest (6) Made of actin protein Forms terminal web
27
describe intermediate filaments
medium thick (8-10) Within skin cells, made of protein keratin Give cell shape, resist stress
28
describe microtubules
thickest (25 nm) Consist of protofilaments made of protein tubulin Radiate from centrosome; can come and go Maintain cell shape, hold organelles, act as railroad tracks for walking motor proteins, make axonemes of cilia and flagella, form mitotic spindle
29
what organelles are considered membranous
``` nucleus mitochondria lysosomes peroxisomes ER (smooth and rough) Golgi complex ```
30
what organelles are considered nonmembranous
ribosomes centrosomes centrioles basal bodies
31
Describe the nucleus and its role in the cell also include what is within the nucleus
- largest organelle - most cells only have one, some have anuclear and some are multinuclear - control center contains: nuclear membrane nucleoplasm
32
what is the nuclear envelope
double membrane around nucleus Perforated by nuclear pores formed by rings of proteins - pores allow for communication in nucleus to cell Function: Regulate molecular traffic through envelope hold two membrane layers together
33
what is the nucleoplasm
material in nucleus Contains: - Chromatin (thread-like) composed of DNA and protein - Nucleoli—masses where ribosomes are produced
34
What is the ER
system of channels (cisternae) enclosed by membrane consists of rough and smooth ER factory line
35
what is the rough ER
parallel, flattened sacs covered with fixed ribosomes Continuous with outer membrane of nuclear envelope Produces phospholipids and proteins of the plasma membrane Synthesizes proteins that are packaged in other organelles or secreted from cell
36
what is the smooth ER
Lack ribosomes Cisternae thought to be continuous with rough ER Synthesizes steroids and other lipids Detoxifies alcohol and other drugs Calcium storage
37
what are ribosomes and their function
small granules of protein and RNA Found in nucleoli, in cytosol, and on outer surfaces of rough ER, and nuclear envelope They “read” coded genetic messages (messenger RNA) and assemble amino acids into proteins specified by the code protein synthesis for both internal and exportive use
38
difference between free and fixed ribosomes
“Free” ribosomes produce proteins for use within the cell (cytoskeleton) “Fixed” ribosomes, attached to RER, produce proteins destined for export
39
what is the Golgi complex
a system of cisternae that synthesizes carbohydrates and puts finishing touches on protein synthesis
40
what is the function of the Golgi complex
Receives newly synthesized proteins from rough ER Sorts proteins, splices some, adds carbohydrate complexes to some, and packages them into membrane-bound Golgi vesicles, adds “docking markers”, etc. vesicles can become 1. lysosomes 2. migrate/fuse to plasma membrane 3. secretory vesicles store protein prod for later
41
what are the digestive organelles
lysosomes peroxisomes
42
what is a lysosome and its fucntion
package of enzymes bound by a membrane Generally round, function: -digest whatever needs digesting - intreacellular hydrolytic digestion of proteins, nucleic acids, phospholipids, complex CHO, etc - autophagy: digestion of cell's surplus organelles - autolysis: cell suicide digestion of a surplus of cellby itself
43
what is a peroxisome plus function
resemble lysosomes but contain different enzymes and are produced by endoplasmic reticulum Function: - is to use molecular oxygen to oxidize organic molecules - cell reactions result in hydrogen peroxide and peroxisomes digest /break down into H20 and O2 and breaks down eythyl alcohol - Neutralize free radicals, detoxify alcohol, other drugs, and a variety of blood-borne toxins - In all cells, but abundant in liver and kidney
44
what is mitochondria | no function here
organelle specialized for ATP production has a double membrane 1. inner membrane has folds = cristae 2. spaces between cristae = matrix matrix -contain ribosomes, enzymes needed for ATP, small circular DNA (mtDNA)
45
what is the function of mitochondria
extract E from organic molecules and transfer to ATP
46
what is a centriole plus function
short cylindrical assembly of microtubules - needed for cell division/reproduce - float around until needed
47
what are the two kinds of inclusions
1. stored cellular products - glycogen granules, pigment, fat 2. foreign bodies - viruses, intracellular bacteria, dust particles, debris from phagocytized cells NOT ESSENTIAL FOR SURVIVAL