A&P 1 Test 2

cell membrane is an effective barrier between ECF and cytosol, because the ________ has 2 key properties:

parts that interact with water in both fluid compartments ____ falling apart

parts that repel water, keeping ECF and cytosol ______

phospholipid bilayer, without, separated

Phospholipids are ______

amphipathic

_________ polar head phosphate group facing each fluid compartment and _________ 2 fatty acids that face one another forming a water-resistant barrier

hydrophilic, hydrophobic

contains intracellular fluid or cytosol, separates it from extracellular space (contains ECF)

intercellular space

ECF that is not blood vessels

interstitial fluid

a main component of plasma membranes, 2 basic types:

intergral proteins, peripheral proteins

span entire plasma membrane aka transmembrane proteins

integral proteins

found only on on side of plasma

peripheral proteins

_____ that bind to ligands. Chemical messengers that trigger sequence of events within cell

receptors

speed up chemical reactions; vita to maintaining homeostasis

enzymes

when bound to cytoskeleton they give cells shape and help maintain structural integrity

structural support

link adjacent cells to another, ______ cells within a tissue and/or allowing cell to cell communication

anchoring

lipid molecule stabilizes plasma membrane's fluid structure during temperature change

cholesterol

carbohydrate bound to either lipid or protein, serve to identify cell as part of body and for cell

glycolipids and glycoproteins

allowing certain molecules to cross while prohibiting passage of other molecules; critical to survival of cell, substance may cross plasma membrane is several ways

selective permeable

no expenditure of energy

passive transport

requires energy

active transport

3 variables determine how a substance moves across the plasma membrane

type of substance, plasma membrane permeability to substance, concentration of substance in cytosol and ECF

passive transport include the following processes

diffusion, simple diffusion, facilitated diffusion, osmosis

basic force that drive passive transport, more dye molecules are found in fluid on bottom of beaker

concentration gradient

movement will continue until _______

equilibrium

movement of solute molecules from high to low concentration; moving down or with its concentration gradient until equilibrium is reached

diffusion

mostly nonpolar solutes like oxygen, carbon dioxide, lipids, and hydrocarbons, pass straight through without need for membrane protein

simple diffusion

water always moves to _______

dilute

driving force exerted by solute molecules; cause water molecules to move until equilibrium (no net movement) is reached

osmotic pressure

channel proteins water passes through primary route for osmosis of water. A small amount of water is able to pass through phospholipid bilayer directly

aquaporins

Way to compare osmotic pressure gradients between two solutions - cytosol and ECF

tonicity

2 fluids have approximately same concentration of solute; no net movement of water across plasma membrane and no volume changes in either fluid compartment

tonicity isotonic

solute concentration of ECF is higher than inside cell, more water molecules inside cell than outside, osmotic pressure gradient pulls water out of cell and cell shrinks or crenates

hypertonic

solute concentration of ECF is lower than inside cell, more water molecules is ECF than inside cell, osmotic pressure gradient pulls water into cell causing the cell to swell possibly lyse (rupture)

hypotonic

requires energy in form of ATP, solutes move against their concentration gradients from low concentration to high concentration

active transport

both primary and secondary active transport processes use plasma membrane carrier proteins called

pumps

pumps 1 substance through membrane in 1 direction either into or out of cell

uniport

pumps 2 or more substances through plasma membrane in same direction, either into or out of cell

symport

pumps transport 2 or more substances in opposite direction

antiport

pumps solute against its concentration gradient using energy from hydrolysis of ATP

primary active transport

vital for maintenance of Na+ and K+ concentration gradient homeostasis, Na+ concentration is 10 times greater in ECF than cytosol and K+ concentration is 10 times greater in cytosol than in ECF

sodium-potassium pump

pump maintains these steep concentration gradients by transporting __________ against their concentration gradients for every ATP molecule hydrolyzed

3 Na+ out and 2 K+ into the cell

uses ATP indirectly to fuel a transport pump, ATP is used to create and maintain a concentration gradient of one substance

secondary active transport

small sacs filled with large molecules too big to transport by other means

vesicles

allows them to fuse with or be formed from plasma membrane or other membrane-bound organelles

active transport via vesicles encoles in a phospholipid bilayer

phagocytosis (cell eating) cells ingest large particles like bacteria or dead or damaged cells or parts of cell

endocytosis

cells engulf fluid droplets from ECF

pinocytosis (endocytosis)

similar to pinocytosis; uses receptors to fill vesicles with a specific molecules

receptor-mediated endocytosis

large molecules exit the cell known as secretion vesicles fuse with plasma membrane, opening into ECF

exocytosis

molecules are brought into cell by endocytosis, transported across cell to opposite side and then secreted by exocytosis

transcytosis

cellular machinery with specific functions vital to maintaining homeostasis; some are separated from cytosol by membrane compartmentalization while others are not enclosed in a membrane

cytoplasmic organelles

cytoplasmic organelles membrane-bound include:

mitochondria, peroxisomes, endoplasmic reticulum, golgi apparatus, lysosomes; perform functions that could be destructive to cell

organelles not enclosed in membrane include

ribosomes and centrosomes

provide majority of ATP used in cell; power plant of cell; each mitochondrion has its own DNA, enzymes, and ribosomes

mitochondria

inner membrane that is highly folded

cristae

membrane-bound organelles; use oxygen to carry out several chemical reactions that produce hydrogen peroxide (H2O2)

peroxisomes

oxidizes toxic chemicals to less toxic compounds that can be eliminated from body before causing damage

peroxisomes

break down fatty acids into smaller molecules used for energy production or other anabolic reactions

catabolic reactions

tiny granular non-membrane-bound organelles where protein synthesis take place

ribosomes

ribosomes

________ usually make proteins needed within cell itself, __________ of other cellular structures

free in cytosol, bound to membranes

forms vesicles that exchange proteins and other molecules, synthesize, modify, and package molecules produced within cell

endomembrane system

plasma membrane, nuclear envelope, and following organelles are components of systems

ER, RER, SER, golgi apparatus, lysosomes

large folded phospholipid bilayer continuous with the nuclear envelope exists in two forms, rough ER has ribosomes bound to it, smoother ER does not

ER

products enter ____ lumen, packages secretory proteins into transport vesicles made of a phospholipid bilayer; sent to the Golgi apparatus for further processing

rough ER

essentially no role in protein synthesis. performs following vital functions: stores calcium ions, capable of several detoxification reactions, involved in lipid synthesis

smooth ER

located between RER and plasma membrane, modifies, sorts, and packages, proteins and lipids made by ER

golgi apparatus

products packaged in Golgi can be

- Secreted from cell (exocytosis)

- Become part of plasma membrane

- Sent to lysosome

digest worn-out cells and/or their components: contains digestive enzymes called acid hydrolases, macromolecules are broken down into smaller subunits that can be released to for disposal or reused to manufacture new macromolecules

lysosomes

SER makes ____ and RER makes _____ and each product is packaged into vesicles for transports to golgi

lipid, protein

golgi sorts and further modifies both _____ and _____ and packs them into vesicles, which may take 3 pathways once they exit the golgi:

vesicles may be sent to _____ where they undergo catabolic reactions

vesicles may be incorporated into ____ or membrane of another organelle in cell

vesicles may be sent to the _____

lipid, protein, lysosomes, plasma membrane, membrane

made of several types of protein filaments; dynamic structure able to change function based on needs of cells; creates and internal framework; provides strength, structural integrity, and anchoring sites

cytoskeleton

the cytoskeleton allows for cellular movement where protein filaments are associated with _____ performing specialized functions in different cell types

motor proteins

cytoskeleton contains 3 types of long protein filaments

actin filaments, intermediate filaments, microtubules

thinnest filaments, composed of two intertwining strands of ____ subunits. provide structural support, bear tension, and maintain cell's shape

actin

actin filaments are involved in cellular motion when combined with the motor protein _____

myosin

intermediate filaments

ropelike, made of different fibrous proteins including ___

keratin

intermediate filaments

form much of ______ of cell and ______ organelles in place

framework, anchor

microtubules

largest filaments; hollow rods or tubes composed of subunit _____

tubulin

can be rapidly added or removed allowing for size and shape changes within cell, maintain internal architecture of cell and keep organelles in alignment

microtubules

microtubules

motor proteins ____ and ____ allow vesicles transport along microtubule network

dynein, kinesin

cellular extensions are formed by the inner framework of the cytoskeleton:

microvilli, cilia, flagella

finger-like extensions of plasma membrane with the actin filaments core to help maintain shape

microvilli

microvilli

increase _____ of cells in organs specialized for absorption

surface area

hair like projections composed of microtubules and motor proteins, move in unison to propel substances past the cell, found in great numbers on each cell

cilia

solitary; longer than cilia. Founded only on sperm cells. Beat in a whiplike fashion propelling entire cell

flagella

The nucleus:

directs activities of the other cellular components,

largely determines ___ of protein and ___ at which cells make them

_____ in nucleus contains code for ___ for nearly every protein in body

____ in DNA are executed by several different types of ____ to build a wide variety of proteins

type, rate, DNA, genes, genes, RNA

membrane that surrounds nucleoplasm, DNA and associated proteins in nucleoplasm as a loose structural arrangement known as chromatin. one or more nucleoli are found suspended in nucleoplasm

nuclear envelope

double phospholipid bilayer, surrounds and encloses entire contents of nucleus

nuclear envelope

found where outer and inner envelope membranes come in contact; serve to connect nucleoplasm with cytoplasm; allows substances to move between two locations

nuclear pore

1 extremely long DNA molecule and its associated proteins, organize and fold molecules to conserve space

chromatin

strand of DNA coiled around a group of histone proteins; appears like beads on a string

nucleosome

for synthesis of ribosomal RNA and assembly of ribosomes

nucleoli

process of manufacturing proteins from DNA blueprint using RNA

protein synthesis

production of protein from specific gene

gene expression

protein synthesis is 2 processes make a specific protein:

transcription, translation

gene for specific protein is copied in the nucleus, creating messenger RNA, exits through nuclear pore

transcription

occurs in cytosol, mRNA binds with ribosome, initiating synthesis of a polypeptide consisting of a specific sequence of amino acids

translation

long chain of nucleotides; segment of DNA that determines specific sequence of amino acids in a protein

genes

4 different nucleotides in DNA

A, T, G, C

each 3-nucleotide sequence of mRNA copy is called a

codon

during translation at a ribosome each codon is paired with a complementary tRNA called an

anticodon

list of which amino acid is specified by each DNA triplet

genetic code

changes in DNA due to mistakes in copying DNA or induced by agents called

mutagens

DNA mutations are the basis for many diseases, including

cancer