CHapter 3 Flashcards Preview

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Flashcards in CHapter 3 Deck (57):
1

plasma membrane

Provides cell with structural support, means of communication with its surroundings and other cells, and cell identification surrounds each cell, isolating its internal structures and processes from external environment; surrounds cell and isolates its internal structure; exterior; system of sugars; phospholipid bilayer

2

cytoplasm

gel in between plasma and nucleus
consists of:
cytosol- – intracellular fluid; site of many important chemical reactions
organelles- ; serve to separate potentially damaging chemical reactions from surrounding cell structures (compartmentalization)
cytoskeleton- creates and maintains shape; holds organelles in place; provides means of transportation for substances within cell

3

nucleus

contains DNA which makes protein and RNA; enclosed in nuclear envelope

4

In order for plasma membrane to form an effective barrier between ECF and cytosol, (molecules that make up the phospholipid bilayer) must have what two key properties:

Molecules must have parts that interact with water in both fluid compartments without falling apart
Molecules must have parts that repel water, keeping ECF and cytosol separated

must have polar (hydrophilic) and nonpolar section that must be hydrophobic

5

amphiphilic

have both a phosphate group (hydrophilic polar head) facing each fluid compartment and two fatty acids (hydrophobic tails) that face one another forming a water-resistant barrier; phospholipid is amphiphilic

6

what're the 3 basic parts of a cell?

cytoplasm, nucleus, and plasma membrane

7

integral proteins

span entire plasma membrane; type of membrane protein

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peripheral proteins

found only on one side of plasma membrane or other; type of membane protein

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enzymes

speed up chemical reactions; vital to maintaining homeostasis

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ECF

extracellular fluid

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Structure function core principle

Cells vary widely in size and structure to enable them to better perform specialized functions

12

do red blood cells have a nucleus?

no

13

what does chromatin condense into?

46 chromosomes

14

can small uncharged nonpolar molecules go thhrough the phospholipid bilayer easily?

yes

15

functions of the membrane proteins (5)

-carry and transport other substances
-signal transduction have a particular site will allow substance/chemical to bind which will change shape of site which will cause a cascade of other reactions
-enzymes
-structural support
-conserve/hold together particular cells

16

selectively permeable

, allowing certain molecules to cross it while prohibiting passage of other molecules; critical to survival of cell; phospholipid is sp

17

how can a substance move across a plasma membrane?

some do not require imput of energy (passive transport mechanisms); other processes do require energy (active transport processes)

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how to determine if a substance will move across the pm by active transport or passive?

Type of substance
Plasma membrane permeability to substance
Concentration of substance in cytosol and ECF

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Concentration gradient

basic force that drives many types of passive transport

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simple diffusion

mostly nonpolar solutes like oxygen, carbon dioxide, lipids, and hydrocarbons; pass straight through phospholipid bilayer without need for membrane protein; no energy oxygen move high concentration to low

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diffusion

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

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facilitated diffusion

involves charged or polar solutes such as ions and glucose; cross phospholipid bilayer with help of a membrane protein (carrier or channel)

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osmosis

type of diffusion; when the cell can't reach equilibrium, this happens; it is a passive process in which a solvent (usually water) moves across a membrane; concentration of solute molecules causes water to move down concentration gradient

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osmotic pressure

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

25

from where does water move across the membrane?

Water moves from area with lower concentration of solute (more water molecules) across membrane to area with higher concentration of solute (less water molecules

26

how does water move across a plasma membrane?

1. Water passes through channel proteins known as aquaporins; primary route for osmosis of water
2. A small amount of water is able to pass through phospho-lipid bilayer directly

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tonicity

way to compare osmotic pressure gradients between two solutions – cytosol and ECF

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isotonic

denoting or relating to a solution having the same osmotic pressure in the inside and outside, especially one in a cell or a body fluid.

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hypertonic

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; more solute ourside than inside

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hypotonic

solute concentration of ECF is lower than inside cell; more water molecules in ECF than inside cell; osmotic pressure gradient pulls water into cell causing the cell to swell and possibly rupture or lyse; less solute outside of cell

31

what kind of energy does active transport require?

Active transport processes require energy in form of ATP to proceed as solutes move against their concentration gradients from low concentration to high concentration

32

sodium potassium pump

The process of moving sodium and potassium ions across the cell membrance is an active transport process involving the hydrolysis of ATP to provide the necessary energy.

33

electrophysiology

Electrical potential found across plasma membrane is known as a membrane potential; study of these potentials is called electrophysiology

34

organelles

are 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

35

list membrane bound organelles

: mitochondria, peroxisomes, endoplasmic reticulum, Golgi apparatus, and lysosomes; perform functions that could be destructive to rest of cell

36

what organelles are not enclosed in a membrane?

ribosomes and centrosomes

37

what is the function of the mitochondria?

“power plant” of cell; membrane-bound organelles involved in chemical energy production; provide majority of ATP used in cell

38

cristae

mitochondria membrane is double bilayer structure with smooth outer membrane and inner membrane that is highly folded into cristae

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peroxisomes

produce hydrogen peroxide; break down chemicals and get rid of them

40

rough ER (FUNCTION)

has ribosomes (protein synthesis);
1. Products enter RER lumen; incorrectly folded polypeptide chains are detected and sent to cytosol for recycling
2. Most proteins that enter RER are for transport out of cell
3. Packages secretory proteins into transport vesicles made of a phospholipid bilayer; sent to the Golgi apparatus for further processing
4. Produces membrane components for membrane-bound organelles and plasma membrane, including integral and peripheral proteins

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smooth ER (FUNCTION)

no ribosomes; Stores calcium ions, lipid synthesizers, detoxification

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golgi apparatus

– located between RER and plasma membrane – group of flattened membranous sacs filled with enzymes and other molecules; proteins and lipids from ER are modified, sorted, and packed for export ( to fuse with plasma membrane)

43

what is the endomembrane system?

process where lipids go from nucleus, to ER, to Golgi

44

lysosomes

organelles responsible for digestion of worn out cell components or whole cells in some cases; if there's 1 type of acid component missing, it can cause a disease; breaking material down

45

what is the cytoskeleton made up of? funcion?

water
function:
help organize other organelles, help cell movement and framework, allows cellular movement

46

list the cellular extensions of a cell

Microvilli
Cilia
Flagella

47

microvilli. function. location.

f: helps absorb nutrients, help maintain shape, Increase surface area
location:

48

cilia. function. location.

f: Move in unison to propel substances past the cells
l:

49

flagella. function. location.

f: Beat in a whiplike fashion propelling entire cell (unlike cilia – propel materials past the plasma membrane
l: sperm cells

50

DNA is executed by diff types of ____

RNA

51

nucleus. function

governing body that directs activities of the other cellular components; largely determines type of proteins and rate at which cell makes them

52

the nuclear envelope surronds what?

membrane that surrounds nucleoplasm (cytosol-like gel containing many components – water, free nucleotides, enzymes, other proteins, DNA, and RNA)

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chromatin

stretched on DNA; organizes and folds molecule to conserve space

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chromosomes

chromatin threads coil tightly and condense into thick structures

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sister chromatids

identical copies of each chromosome; made in preparation for cell division; connected to one another at region called centromere

56

List the order that DNA is made to proteins.

- DNATranscriptionmRNATranslationProtein
Gene expression – production of protein from specific gene
Two processes actually make a specific protein:
Transcription – process where gene for specific protein is copied; creating messenger RNA (mRNA); exits through nuclear pore
Translation occurs in cytosol; mRNA binds with ribosome initiating synthesis of a polypeptide consisting of a specific sequence of amino acids

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protein synthesis

Protein synthesis – process of manufacturing proteins from DNA blueprint using RNA