Cells Flashcards
(123 cards)
1
Q
the cell
A
the basic structural and functional unit of living organisms.
2
Q
biochemical activities of cells are determined and made possible by
A
…. subcellular structures (organelles)
3
Q
generalized eukaryotic cells - 3 main parts?
A
plasma membrane (plasmalemma)
cytoplasm
nucleus
4
Q
plasma membrane
A
selectively permeable barrier
cellular communication
5
Q
Each chromosome consists of
A
a single molecule of DNA and associated packaging proteins
6
Q
“A phospholipid bilayer with associated integral and peripheral proteins.”
A
Plasma membrane
7
Q
Fluid Mosaic Model
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arrangement of molecules within the plasma membrane
lipids are barriers
molecules within the membrane I.e. proteins are “gatekeepers”
8
Q
self-sealing if torn or punctured due to
A
fluidity
9
Q
fluid membrane allows cell movement, growth, division, etc through this property
A
fluidity
10
Q
plasma membrane allows passage of
A
lipid-soluble substances
11
Q
plasma membrane is a barrier to
A
charged or polar substances
12
Q
bilayer occurs because lipids are ____
A
amphipathic, having both polar and non polar parts
13
Q
The lipid bilayer consists of:
A
Phospholipids, Cholesterol, and Glycolipids
14
Q
what mediates membrane fluidity
A
cholesterol
15
Q
What makes lipid bilayer less fluid (and stronger) at normal body temperatures ?
A
cholesterol
16
Q
What Increases membrane fluidity at lower temperatures?
A
cholesterol
17
Q
cholesterol is weakly? due to what
A
amphipathic… small -OH group
18
Q
Cholesterol forms ____ bonds with heads of ____ and _____, and fills the space between fatty acid tails
A
hydrogen;
phospholipids and glycolipids
19
Q
______ form a lipid bilayer - cholesterol and glycolipids (sugar-lipids) also contribute.
A
Phospholipids
20
Q
______ extend into or through the bilayer.
______ span the entire lipid bilayer.
______ attach to the inner or outer surface but do not extend through the membrane.
A
Integral proteins
Transmembrane proteins (most integral proteins)
Peripheral proteins
21
Q
______ are membrane proteins with a carbohydrate group attached that protrude into the extracellular fluid.
A
Glycoproteins
22
Q
The _____ is the entire “sugary coating” surrounding the membrane
A
Glycocalyx
23
Q
The glycocalyx is made up of made up of the carbohydrate portions of the ___ and ____
A
glycolipids and glycoprotein
24
Q
two classes of membrane proteins
A
integral and peripheral
25
peripheral proteins attach to ___ or ___
phospholipid heads or to integral proteins
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protein on one side of the membrane
peripheral
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Plasma membrane proteins
```
ion channels
transporters
receptors (I.e. ligand)
enzymes
cell-identity markers
```
28
6 different membrane proteins (ICRELC)
```
▪ Ion channels
▪ Carriers
▪ Receptors
▪ Enzymes
▪ Linkers
▪ Cell identity markers
```
29
allows specific ions to move through water-filled pore
Ion Channel (integral)
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carries specific substances across membrane by changing shape (I.e. amino acids)
Carrier (integral) also known as the "TRANSPORTERS"
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also known as the "transporters"
carrier membrane protein
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Recognizes specific ligand and alters cell's function ins some way (I.e. ADH in kidneys changes permeability of plasma membranes)
Receptor (integral)
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Catalyzes reaction inside or outside cell (depending on which direction the active site faces). I.e. lactase splitting disaccharide
Enzyme (integral and peripheral)
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Anchors filaments inside and outside the plasma membrane, providing structural stability and shape fo the cell. May also help with MOVEMENT or LINKING cells together
Linker (integral and peripheral)
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Distinguishes your cells from anyone else's (unless identical twins) I.e. Major Histocompatibility (MHC) proteins
Cell-Identity Marker (glycoprotein)
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Cell-Identity marker think....
glycoprotein and MHC
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sugars attached to proteins or lipids on the outer face of the plasma membrane
glycocalyx
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glycocalyx may change continuously... often seen in?
cancer
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Rule of Thumb: small, neutrally-charged, lipid-double substances can....? (special case?)
Easily or Freely pass the membrane (water is special case)
40
Water (unique) and gases
Small, fat-soluble molecules
charged ions (K+,Na+, Ca++, HPO4-, etc)
large, water-soluble molecules (e.g. proteins)
pass easily
pass fairly easily
don't pass
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the lipid bilayer is permeable to nonpolar, uncharged molecules such as __, ___, and ____
oxygen, carbon dioxide, and steroids
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the lipid bilayer impermeable to ions and large uncharged
| polar molecules such as _____
glucose
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the lipid bilayer slightly permeable to small uncharged polar molecules such as ___ and ____
water and urea
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Substances that are nonpolar and lipid soluble move into and out of the cell by _____ _____ through the plasmalemma. These include:
COAFF
```
simple diffusion;
COAFF
– Oxygen
– Carbon dioxide
– Fats
– Alcohol
– Fat-soluble vitamins (A, D, E, and K)
```
45
Some polar substances can diffuse across the plasma membrane because they are small enough:
water and urea
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Most water soluble particles are not able to diffuse
| through the lipid bilayer because they are repelled by the ?
nonpolar hydrocarbon chains
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Due to its hydrophobic interior, the plasma membrane is a physical barrier to unhindered diffusion, but molecules will passively diffuse if they are…
– Lipid soluble, or
– Small enough to pass through the membrane pores, or
– Assisted by carrier molecules
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concentration gradient
chemical
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electrical gradient
charges (electrical)
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electrochemical gradient
chemical and electrical charges
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Oxygen molecules and sodium ions are more concentrated in the
ECF or extracellular fluid
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Carbon dioxide and potassium ions are more concentrated in the
cytosol
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Passive processes of movement = ?
| ex's?
```
no energy expenditure required
– Diffusion
• Simple diffusion
• Osmosis
• Facilitated diffusion
– Filtration
```
54
Active processes of movement require?
ex's?
(energy expenditure required)
```
– Active transport
• Primary active transport
• Secondary active transport
– Bulk transport (vesicular transport)
• Exocytosis • Endocytosis • Transcytosis
```
55
is the passive spread of particles through random motion, from areas of high concentration to areas of low concentration.
diffusion
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Diffusion is affected by:
– the amount of substance and the steepness of the concentration gradient.
– Temperature
– Surface area
– Diffusion distance
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Osmosis
▪Diffusion of solvent (water) through a semipermeable membrane
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Osmosis follows the rules of diffusion:
▪Follows the rules of diffusion:
– Requires a concentration gradient
– Movement is from a compartment with a higher water concentration (lower solute concentration) to an area of lower water concentration (higher solute concentration)
▪Requirements:
– Semipermeable membrane
– At least one “osmotically active” solute, i.e., one that is in higher concentration on one side and can’t pass through the membrane
▪Osmotic pressure
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tonicity of a solution is described relative to the tonicity of the...
intracellular fluid (cytosol) of the cell(s) involved
60
Some molecules that the cell requires are too polar to diffuse through the lipid bilayer, or, like glucose, are too large to pass through membrane pores so they:
solute binds to protein carrier on one side of the membrane and is released on the other side after the transporter undergoes a change in shape (FACILITATED DIFFUSION)
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water soluble vitamins cannot pass
cytoplasmic membrane
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Solutes that move by ___ ____ include glucose, fructose, galactose, and some vitamins
facilitated diffusion
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Foot stomp: In _____, the energy is derived directly from the breakdown of ATP. In the _____, the energy is derived secondarily from energy that has been stored in the form of ionic concentration differences between the two sides of a membrane.
primary active transport
| secondary active transport
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sodium-potassium pump is a form of?
primary active transport (against the weird K - concentration gradient)
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In _____, the energy stored in a Na+ or H+ concentration gradient is used to drive other substances across the membrane against their concentration gradient
secondary active transport
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The Na+ or H+ concentration gradient was established by primary active transport, so secondary active transport indirectly uses energy obtained from _____?
the hydrolysis of ATP.
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carry two substances across the membrane in
| opposite directions.
Antiporters
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carry two substances across the membrane in the
| same direction.
Symporters
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examples of antiporters
Sodium and calcium, or sodium and hydrogen
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examples of symporters
sodium and glucose or sodium and amino acid
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symporters and antiporters use ___ active transport
secondary
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three types of endocytosis?
– receptor-mediated endocytosis
– Phagocytosis
– bulk-phase endocytosis (pinocytosis)
73
bulk transport or vesicular transport is ___ transport
active (uses energy)
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highly selective endocytosis, cells take up specific ligands
receptor mediated endocytosis
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bulk phase endocytosis
pinocytosis or cell drinking (invaginating with a "sip" of ECF)
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pinocytosis
bulk phase or cell drinking
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phagosome + lysosome =
phagocytosis
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clathrin with endosome to lysosome =
receptor mediated endocytosis
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lysosome + vesicle with dissolved solutes
pinocytosis
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exocytosis examples
– secretory cells that produce substances such as digestive enzymes, hormones, mucus, etc.
– nerve cells, which release neurotransmitters
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transcytosis
Most often occurs across endothelial cells lining blood vessels wherein materials are moved between the blood plasma and interstitial fluid
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2 components of cytoplasm
cytosol and organelles
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the site of chemical reactions, energy release from them, etc
cytosol
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spherical body that produces ribosomes
Nucleolus
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a double membrane that separates the nucleus from the cytoplasm
Nuclear envelope
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look at image on slide 60
good work
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a blob of ribosomal RNA
Nucleolus
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produces both ribosomal subunits
Nucleolus
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produces both ribosomal subunits
Nucleolus
90
▪A dense complex of RNA, DNA, and protein
▪Forms around the portions of certain chromosomes having regions that code for production of ribosomes
▪Produces both ribosomal subunits.
▪Catch phrase is “blob of ribosomal RNA”
Nucleolus
91
▪A complex of DNA and proteins
| ▪represents the relaxed, uncoiled chromosomes of the interphase nucleus
Chromatin
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site of protein synthesis
ribosomes
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where amino acids are assembled into proteins (on what)
ribosomes
94
small and large subunit, either free or attached
ribosomes
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both ribosomal subunits are manufactured in the....
nucleolus
96
reside, disassembled, in the cytoplasm until needed
ribosomal subunits
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Subunit which initiates translation, recruits the large ribosomal subunit, and reads the mRNA
The small subunit
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subunit which joins the amino acids to form a polypeptide chain
The large subunit
99
ER which is more linear
Rough endoplasmic reticulum (RER)
100
ER which is a network of tubules
smooth endoplasmic reticulum (SER)
101
A stack of 3-20 flattened, membrane- enclosed sacs called cisternae
Golgi Complex
102
Golgi
– Transport vesicles arriving from the rough ER fuse with the ___ face of the Golgi
– Secretory vesicles, lysosomes, and peroxisomes bud from the ___ face
cis
trans
103
Golgi complex functions
receive "immature" proteins form rough ER
synthesize carbohydrate
"packing and export mechanism for the cell"
104
▪“The powerhouses of the cell”
▪Have two membranes, outer and inner; the inner folds in many times producing cristae
▪Self-replicating—have their own DNA. Used to establish heredity-only from mother
▪Contain enzymes responsible for cellular respiration and the Krebs cycle
▪Most of the cell’s ATP is produced here (cellular respiration)
Mitochondria
105
mitochondria are about the size of ____ and have their own _____
bacteria; ribosomes
106
Lysosomes are where? contain?
vesicles that form from the Golgi complex and contain powerful digestive enzymes
107
vesicles that form from the Golgi complex and contain powerful digestive enzymes
Lysosomes
108
carry out autophagy (digest old organelles)
| carry out autolysis (digest entire cell)
lysosomes
109
▪Another Golgi complex product ▪Detoxify several toxic substances such as alcohol
▪Abundant in the liver
▪Also break down hydrogen peroxide (H2O2), a byproduct of oxidation, using the enzyme catalase
▪New peroxisomes form from pre-existing ones by enlarging and dividing, so they are self- replicating (but they do not have DNA)
Peroxisomes
110
▪Continuously degrade(destroy) unneeded, damaged, or faulty proteins
▪Found in the cytosol and the nucleus ▪Some diseases may result from failure of proteasomes to function properly, such as the abnormal proteins that accumulate in brain cells of persons with Parkinson disease and Alzheimer disease
Proteasomes (can change shape)
111
▪Membranous sacs within the cytoplasm of cells
▪Commonly formed when part of the plasma membrane folds inward and pinches off during phagocytosis
▪May be associated with lysosomes, forming a digestive vacuole
▪May be for temporary storage of material
Vacuoles
112
▪Located near the nucleus
▪Centrioles: paired, perpendicular cylinders
▪Each cylinder composed of 9 microtubule triplets
▪Function: assembly of microtubules
Centrosome
113
the microtubule organizing center
centrosome
114
```
▪Non-living components within cells
▪Not bounded by membrane
▪Most common
– Glycogen
– Lipids
– Pigments
– Crystals
```
inclusions
115
A cancerous neoplasm (tumor) that tends to metastasize
Malignancy
116
Malignant tumors that arise from epithelial cells.
Carcinoma
117
A general term for any cancer arising from muscle cells or connective tissues.
Sarcoma
118
Alteration in the size, shape,
and organization of cells due to chronic
irritation or inflammation; may progress to
neoplasia if the conditions persist, or revert
to normal if the irritation is removed.
Dysplasia
119
An increase in the number of cells of a tissue due to an increase in the frequency of cell division.
Hyperplasia
120
Metaplasia
The transformation of one cell type into another.
121
-plasia:
“growth, cellular multiplication,”
122
A substance introduced into circulation by tumor cells that indicates the presence of a tumor, as well as it’s specific type; may be used to screen, diagnose, and evaluate a response to treatment, and monitor for recurrence of the cancer.
Tumor marker
123
functions of lysosomes
digest -endocytosis
transport digestion into cytosol
autophagy
autolysis
