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Ch3
the cellular level of organization
41
Anatomy
Undergraduate 3
06/11/2013

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Term
All eukaryotic cells are composed of three parts
Definition

1. plasma membrane

2. cytoplasm

3. nucleus

Term
cytoplasm
Definition
a gelatin-like substance, plus structural fibers and organelles (but not the nucleus)
Term
nucleus
Definition
contains the genetic library of the cell
Term
plasma membrane
Definition

controls passage of materials in and out of cell (semi-permeable, selectively permeable).

-intercellular face-side faces cytoplasm.

-extracellular face-side faces outwards

 

controls interactions/communication with other cells(sensitivity)

-identification

-protection

-adhesion

Term
Lipids constitute ______ of the plasma membrane
Definition
90-99%
Term
Membrane Lipids
Definition

Phospholipid bilayer

-75% of the lipids

-hydrophilic heads (phosphate) on each side

-hydrophobic tails in the center

Term
membrane lipid(2)
Definition

Cholesterol

-affects membrane fluidity (makes bilayer stronger but less fluid at body temp, and has opposite effect at low temps

Term

Membrane Lipids (3)

 

Definition
-Glycolipids: found only on extracellular face, contriubte to glycocalyx (carbohydrate coating on cell surface, act as a molecular signal so that cells can recognize one another).
Term
Membrane Proteins
Definition

integral proteins contribute to the moelcules found in the plasma membrane.

-transmembrane proteins

--pass completely through membrane

--most are glycoproteins

peripheral proteins: adhere to the inner or outer surface of the membrane

Term
glycoproteins
Definition
membrane proteins with a carbohydrate group attached that protrude int the extracellular fluid.
Term
glycocalyx
Definition
entire "sugary coating" surrounding the membrane (made up of the carbohydrate portions of the glycolipids and glycoproteins).
Term
membrane protein function
Definition

pores, ion channels, carrier/transporters, pumps(semi-permeable)

receptors, identity(sensitivity), adhesion, messanger systems, enzymes

Term
ion channel(integral)
Definition
allows specific ion to move through water-filled pore. most plasma membranes include specific channels for several common ions
Term
carrier(integral)
Definition
carries specific substances across membrane by changing shape. for example, amino acids, needed to synthesize new proteins, enter body cells via new carriers. Carrier proteins are also known as transporters.
Term
receptor(integral)
Definition
recognizes specific ligand and alters cell's function in some way. for example, antidiuretic hormone binds to receptors in the kidneys and changes of water permeability of certain plasma membrane
Term
simple diffusion
Definition

movement of particles across membrane from area of high concentration to an area of low concentration (down or with the concentration gradient). 

-small uncharged solutes(most gases and lipids)

Term
faciliated diffusion
Definition

-proteins allow solutes across cell membrane(like a door)

-solutes still move down concentration gradient

--charged particles (ions, amino acids, nucleotides) 

Term
osmosis
Definition

movement of water through a selectively permeable membrane

-from an area of more water to an area of less water

-from an area of less solutes to an are of more solutes

-aquaporins are channel proteins in cell membrane that allow water to move freely in our out of the cell, and is determined by the tonicity (salt concentration) of the solution

Term
active transport
Definition

protein-mediated, active transport of solute goes across membrane against its concentration gradient.

-energy (usually atp) required

-prominent example is the sodium-potassium pump

-3 Na+ out/ 2K+ in/ 1 ATP used

Term

primary vs secondary active transport

 

Definition

primary: -aka dependent

-directly uses energey from atp

 

secondary:-aka atp-independent

-uses energy from ion gradients (usually na+)

-the gradient along atp

Term
antiporters
Definition

carry two substances across the membrane in opposite directions.

-secondary active transport mechanism

Term
symporters
Definition

carry two substances across the membrane in the same direction.

-secondary active transport mechanisms

Term
bulk(vesicular transport)
Definition

transport of large particles or fluid droplets through membrane in bubble-like vessicles of plasma membrane, uses atp.

-endocytosis and exocytosis

Term
exocytosis
Definition
vesicular transport out of the cell
Term
endocytosis
Definition

vesicular transport into cell

-phagocytosis: engulfing large particles

Term
organelles specialized structures within the cell
Definition

-ribosomes

-endoplasmic reticulum(smooth and rough)

-golgi complex

-lysosomes

-mitochondria

-nucleus

Term
cytosol
Definition

intracellular fluid, sorrounding the organelles.

-cytoskeleton

Term
cytoskeleton
Definition
network of protein filaments throughout the cytosol, provides structural support for the cell
Term
types in the cytoskeleton
Definition

microfilaments

intermediate filaments

microtubules

Term
centrosome
Definition
a dense network of small protein fibers locates near the nucleus of a cell, consists of two centrioles and a pericentrioler material
Term
centrosome
Definition
a dense network of small protein fibers located near the nucleus of a cell, consists of two centrioles and pericentriolar material
Term
cilia
Definition
short, hair like projections from the cell surface, move fluids along a cell surface
Term
flagella
Definition
longer than cilia, move an entire cell, only example is the sperm cell's tail
Term
ribosomes
Definition
a cellular structure composed of a small subunit and a large subunit that contain ribsomal rna and ribosomal proteins; sites of protein synthesis
Term
endoplasmic reticulum
Definition
network of membranes or channels that serve in intracellular transporation, support, storage, synthesis, and packing of molecules
Term
rough er
Definition
portions where the surface is studded with ribosomes, produces various proteins
Term
smooth er
Definition
portions where the surface does not have ribosomes, synthesizes fatty acids and steroids, detoxifies certain drugs
Term
golgi complex
Definition

consists of 3-20 flattened, membranous sacs called cisternae.

-accepts proteins from rough ER

-modify, sort, and package proteins for transport to different destinations

Term
lysosomes
Definition
vesciles that form from the golgi complex and contain powerful digestive enzymes
Term
nucleus
Definition

spherical or oval shaped structure

-usually most prominent feature of a cell

-nuclear envelope: a double membrane that seperates the nucleus from the cytoplasm

-nuclear pores: numerous openings in the nuclear envelope, control movement of substances between nucleus and cytoplasm

-nucleolus: spherical body that produces ribosomes and chromosomes

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