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Flashcards in CH. 3 Cells I Deck (56):
1

Cells

-Smallest living units of biology.
-They carry out all chemical activities needed to sustain life.
-Basic structural and functional unit of living organisms.
-Vary in shape, size, and function.
-Trillions of cells organized in groups of tissues in organs.
-Human body is based on proper cell function, by examining them at cellular level we can study normal and disease states.
-can study cellular activity of the bod by measuring vital signs (body temp, respiration rate, blood pressure)
- cells link monomers (CHON) into molecules polymers. Like carbohydrates (C6H12O6), proteins and lipids.
-Cells produce enzymes that perform many chemical reactions (assembly and breakdown)
-cells share common structures that we study as generalized cell model.

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Uses ATP as energy source

O2 + C6H12O6 -> CO2 + H2O + (ATP)
Energy for life activities

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3 main parts of the cell:

1. Plasma membrane
2. Cytoplasm with organelles
3. Nucleus/ DNA

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Plasma Membrane

Membrane is (attached sugar groups)
Composed of phospholipids, cholesterol, and proteins, that encloses cell contents outer limiting cell membrane.

Fluid Mosaic Model: membrane is neither rigid nor static in structure but instead highly flexible and can change its shape and composition through time.

Cell barrier transports substances in and out of the cell, keeps resting environment. Separates Intra/extracellular fluids of the body.

extracellular (out) OOOOO -receptors for hormones
{}{}{}{}{} cell to cell recognition
Intracellular (in) OOOOO- transport proteins

Produces a charge difference called membrane potential across the membrane by regulation of intracellular and extracellular ion concentrations.
Inside is negatively charged with respect to outside positively charged.

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Plasma Membrane: construction
Phospholipids

Cell-to-cell recognition Receptor signals for (do you belong or do I need to attack).

Hydrophilic head groups face water in the interior and exterior of the cell.

Hydrophobic tails face each other on interior of membrane

Can keep some substances from flowing directly though membrane.

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Plasma Membrane: construction
Proteins

Peripheral (transmembrane): one sided, Carries bind substances to move it through membrane.

Integral proteins: both sided, not embedded in bilateral can be removed / support membrane from cytoplasmic side.

Function as transport channels, receptors for signal transduction, attachment to cytoskeleton and extracellular matrix, enzymatic activity, intercellular joining, cell-to-cell recognition, etc.

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Plasma Membrane: construction
Cholesterol

Stabilizes membrane while decreasing the mobility of the phospholipids and the fluidity of the membrane.
Amount determines how fluid membrane will be.

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Plasma Membrane: Selective Permeability

Transport= permeability can go through
Diffusion
Some substances (small, hydrophobic, not charged) can cross more easily than others

But if large charged hydrophilic go through gate protein
Membrane transport-movement of substances into and out of the cell.

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Plasma Membrane: Selective Permeability
Simple Diffusion

Nonvolatile and lipid silk able substances diffuse through movement of molecules done their concentration gradient

(High -> Low ) No energy required.

Solutes are lipid-soluble materials and small enough to pass through membrane pores
(Ex: fat solvable vitamins)

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Plasma Membrane: Selective Permeability
Facilitated Diffusion

kinetic energy
Movement of solute from done its concentration gradient (High -> Low).

Diffusion with transport/ carrier proteins.
Mechanism for glucose, amino acids, and ion transport

Specificity for a single type of molecule.
Competition among molecule of similar shape.
Saturation-rate of transport limited to number of available transport proteins.

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Plasma Membrane: Selective Permeability
Active Transport

Movement of ions uphill against concentration gradient, from (Low -> High)
Uses transport protein and energy ATP is required.
Example: Na+/K+ exchange pump that creates electrical potentials across membranes.

Cardiac skeletal, muscle, neuron function.

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Plasma Membrane: Selective Permeability
Vesicular Transport

Transport of Large particles and macromolecules across plasma membrane inside bubble sacs called vesicles.

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Plasma Membrane: Selective Permeability
Vesicular Transport: Endocytosis:
Phagocytosis

Endocytosis (Bring vesicle in)
Bulk or large molecule transport into cell

Phagocytosis: (function) protect body from bacteria, dead tissue, etc.
Lysosomes are in charge of their destruction merge with phagocytosis. White blood cells engulf invaders or cell debris and take into cell

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Plasma Membrane: Selective Permeability
Vesicular Transport: Endocytosis
Pinocytosis

"Cell shrinking" small stuff
Surrounds a small volume of extra cellular fluid containing dissolved molecules.
Routine activity for cells by sampling fluid to absorb nutrients.

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Plasma Membrane: Selective Permeability
Vesicular Transport: Endocytosis
Receptors mediated Endocytosis

When protein receptors are activated on the surface the membrane takes in substances from the outside.
Clinical: Hypercholesterolemia:
Cholesterol receptors bring cholesterol out of blood into the cell
HH normal cholesterol receptors
Hh 1/2 # cholesterol receptors (high ch,even with low ch. diet)
hh no cholesterol diet (have heart attacks at young age)

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Plasma Membrane: Selective Permeability
Vesicular Transport: Exocytosis

Exocytosis: bring vesicle out
Bulk or large molecule transport out of cell.
Hormone-secretion and mucus secretion neurotransmitter release.

Target T-snare, V-snare

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Plasma Membrane: Selective Permeability
Osmosis

H2O always more hypotonic to hypertonic.
Important because large volume changes caused by water movement disrupt normal cell function.

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Plasma Membrane: Selective Permeability
Osmosis

Based on its total solute concentration
Tonicity based on how the solution affects the cell volume.
Diffusion of water across a selectively permeable membrane from an area of High H2O to Low H2O

Affected by total concentration of all solute particles in a solution (called osmolarity)

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Plasma Membrane: Selective Permeability
Osmosis
Hypotonic

Low solute concentration- More dilute compared to human body plasma compartment
Cells plump up as H2O enters them

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Plasma Membrane: Selective Permeability
Osmosis
Hypertonic

high solute concentration compared to human body plasma compartment.

Cell immersed in hypertonic solutions lose H2O and shrink.

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Plasma Membrane: Selective Permeability
Osmosis
Isotonic

Same solute concentration compared to human body plasma compartment.

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Cytoplasm

Synthesize proteins and generate ATP.
Fluid matrix like jello (cytosol of protein usage and water embedded organelle structures inclusions. The cellular material surrounding the nucleus and enclosed by the plasma membrane.

Consists of fluid cytosol contains dissolved salutes, organelles (metabolic machinery of the cytoplasm) and inclusions (stored nutrients, secretory products, pigment granules).

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Mitochondria

Cytoplasmic organelles responsible for ATP generation for cellular activities.

Rodlike, double membrane structure, inner membrane folded into projections called cristae.

Site of the ATP synthesis: powerhouse of the cell.

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Cytoplasm:
Mitochondria

Synthesizes ATP
Provides all energy for all cellular work. Number will increase in cell when energy require the increase.
Most are in kidney and liver. Complex organelle, they contain their own DNA RNA ribosomes can complicate itself.

Two energy releasing pathways

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Cytoplasm:
Mitochondria
Anaerobic Respiration

Start with glycolysis in the cytoplasm

Does not require oxygen
Produces Very little ATP

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Cytoplasm:
Mitochondria
Aerobic Respiration

Starts with glycolysis in mitochondria
Requires oxygen
Produces large amount of ATP

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Ribosomes

Cytoplasmic organelles at which proteins are synthesized.

Dense particles consisting of 2 subunits each composed of ribosomal RNA and protein, free or attached to rough endoplasmic reticulum.

The sites of protein synthesis.

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Cytoplasm:
Ribosomes

Sites of protein synthesis
FREE ribosomes suspended in cytosol and synthesize proteins that will stay inside the cell

ATTACHED to ER will synthesize proteins destined for secretion to outside the cell

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Rough Endoplasmic Reticulum

Membraneous system enclosing a cavity, the cistern, and coiling through the cytoplasm. Externally studded with ribosomes.

Sugar groups are attached to proteins within the cisterns, proteins are bound in vesicles for transport to the Golgi apparatus and other sites.

External face synthesizes phospholipids.

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Cytoplasm:
Rough endoplasmic reticulum

Its ribosomes manufacture/ transport all proteins secreted from cell. "Membrane factory"

Produces integral membrane proteins and phospholipids that form part of all cellular ,\membranes are manufactured.

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Cytoplasm:
Smooth Endoplasmic Reticulum

*enzymes catalyze reactions involved with tasks

Absorb and transport fat, drug detoxification, lipid and cholesterol production, sex//steroid hormone production.

(phenobarbital resistance)

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Smooth Endoplasmic Reticulum

Membrane our system of sacs and tubules free of ribosomes.

Site of lipid and steroid (cholesterol) synthesis, lipid metabolism, and drug detoxification.

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Cytoplasm:
Lysosomes

Demolition crew site of intercellular digestion (self eating) when hurt contain activated digestive enzymes.
Filled with hydrolases enzymes.

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Lysosomes

Organelles that originate from the Golgi Apparatus and contain strong enzymes.

Membrane out sacs containing acid hydrolases.

Site of intracellular digestion.

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Cytoplasm:
Peroxisomes

Detoxification of harmful substances like alcohol and formaldehyde and neutralizes dangerous free radicals that can scramble the structure of biological molecules

Oxidase a and catalases
Hydrogen H2O
Peroxide

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Peroxisomes

Membraneous sacs in the cytoplasm containing powerful oxidase enzymes that use molecular oxygen to detoxify harmful/ toxic substances (free radicals)

The most important enzyme catalase breaks down hydrogen peroxide.

Catalase + Oxidase enzymes in sacs.

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Golgi Apparatus

Membraneous system close to the cell nucleus that packages protein secretions for exports, packages enzymes into lysosomes for cellular use, and modifies proteins destined to become part of cellular membranes.

A stack of flattened membranes and associated vesicles close to nucleus.

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Cytoplasm:
Inclusions

Temporary storage of pigment and fat droplets, etc.

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Cytoskeleton

Cell Skeleton, an elaborate series of rods running through the cytosol, supporting cellular structures and providing the machinery to generate various cell movements.

Microtubules: centrioles
Intermediate filaments:
Microfilamets:

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Cytoplasm:
Cytoskeleton

Small internal rods that determine cell shape and structure, support organelles, and provided machinery needed for transport and cell division

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Centrioles microtubules

Minute body found in pairs near the nucleus of the cell; active in cell division.

Paired cylindrical bodies, each composed of a triplets of microtubules.

Part of centrosome, organize a microtubule network during mitosis to form the spindle and asters form bases of cilia and flagella.

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Cytoplasm:
Centrioles

Within centrosome structure produces fibers (microtubules spindle) necessary for cells to divide and replicate

Are hallow tubes constantly growing determine overall shape of the cell and distribution of cellular organelles mito +lose attach to these tubules powered by ATP use m tubules as tracks or other proteins by hand over hand.

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Cytoplasm:
Cellular Extension

Cilia
Flagella
Microvilli

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Cytoplasm:
Cellular extension
Cilia

Propels other substances
Formed by Centrioles its the bases of cilia and flagella
Hair like projections used to propel substances across the cell surface.
Ex. Trechea, egg to uterus

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Cytoplasm:
Cellular extension
Flagella

Propels itself. Basal bodies
Armed by centrioles longer than cilia
Single tail like projections used to propel entire cell forward.
Ex sperm cell

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Cytoplasm:
Cellular extension
Micro villi

Shaggy hairs that do not move, absorption of monomers. Finger like projections on the surface of some cells that increase surface area for absorption.
intestine Kidney

Mechanical stiffener.

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Nucleus

Control center of a cell, genetic material, clusters of nerve cells bodies in CNS, center of atom (P,N)

Largest organelle surrounded by the nuclear envelope contains fluid nucleoplasm, nucleoli, and chromatin.

Transmits generic info and provide instructions for protein synthesis.

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Nucleolus

Dense spherical bodies in the cell nucleus involved with ribosomal RNA synthesis/ subunit assembly.

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Nuclear Envelope

The double membrane barrier of a cell nucleus.

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DNA

Deoxyribose nucleic acid: found in all living cells that carries the organisms hereditary information.

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Nucleus

Contains genes, control center for cell activities (life)
Recipes for life stored in chemical as form of DNA
All cells gave at least on nucleus at some point.
Dictates amounts of proteins to synthesize in response to signals acting on a cell.

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Nucleus:
Structural Organization
Nuclear envelope with nuclear pores

Nuclear envelope: selective permeable with nuclear pores that is the outer nuclear membrane. Continues with rough ER of cytoplasm.

Regulates entry and exit of molecules and large particles in and out of nucleus (Nucleoplasm within)





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Nucleus:
Structural Organization
Chromatin

Chromatin: (uncoiled DNA)

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Nucleus:
Structural Organization
Chromosomes

Chromosomes: (tightly coiled DNA) packed to divide. When a cell is preparing to divide, the chromatin threads coil and condense enormously to form short bodies called chromosomes to prevent tangles or breaking.

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Nucleus:
Structural Organization
Nucleolus

Nucleolus (RNA for ribosome assembly)

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Nucleus
Structural organization

Nuclear envelope with pores
Chromatin (uncoiled DNA)
Chromosomes (tightly coiled DNA)
Nucleolus (RNA for ribosome assembly )