DENNIS BSC 2010 Exam 2

plasma membrane

a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell, found in prokaryotes and eukaryotes, double layer of phospolipids

cytosol

semifluid interior substance, found in pro and euk

chromosomes

carry genes made of DNA (pro and euk)

cellular metabolism

the logistics of carrying out ____ sets limits on the size of cells

mitochondria

plant and animal cells have ____ that makes ATP

double membrane, lipid bilayer

the nuclear membrane is a ____, each membrane consists of a ______

pores

regulate the entry and exit of molecules from the nucleus

nuclear lamina

shape of the nucleus is maintained by the _____ which is composed of protein filaments

chromatin

DNA and proteins form genetic material called

nucleus

contains most of the cell's genes and is the most conspicuous organelle

nuclear envelope

encloses the nucleus separating it from the cytoplasm

ribosomes

responsible for the conversion of genetic material to protein (protein synthesis); particles made of ribosomal RNA and protein - make proteins

Endoplasmic Reticulum

accounts for more than half of the total membrane in many eukaryotic cells, continuous with the nuclear envelope

smooth er

lacks ribosomes, synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, stores calcium

rough er

ribosomes on surface, has bound ribosomes that secrete glycoproteins, distributes transport vesicles, membrane factory for the cell

Golgi apparatus

___consists of flattened membranous sacs called cisternae

lysozome

a membranous sac of hydrolytic enzymes that can digest proteins, fats, polysaccharides, and nucleic acids

autophagy

the process where lysosomes use enzymes to recycle the cells own organelles and macromolecules

vacuoles

maintenance and storage compartments in cells, can be more than one in a cell

eukaryotic cells

mitochondria are in nearly all

mitochondria

___ have a smooth outer membrane and an inner membrane folded into cristae

cristae

folds in inner membrane of mitochondria, present a large surface area for enzymes that synthesize ATP

Chloroplasts

contain the green pigment chlorophyll

thylakoids

membranous sacs that are stacked to form a granum

stroma

internal fluid of chloroplast

oxygen

used to break down different types of molecules

Cytoskeleton

network of fibers extending throughout the cytoplasms, organizes the cell's structures and activities anchoring many organelles

microtubules

slide, thickest component of the cytoskeleton, hollow rods

centrosome

microtubule organizing center

centrioles

in animal cells, centrosomes have a pair of

cilia and flagella

microtubules control the beating of

dynein

motor protein which drives the bending movements of a cilium or flagellum, means walking

microfilaments

thinnest component of the cytoskeleton, called actin filaments, form the cortex to support the cell's shape

intermediate filaments

fibers with diameters in a middle range, more permanent cytoskeleton fixtures

cell wall of plants

Extracellular structure distinguishing plant cells from animal cells

cell wall, water

the ___ helps cells maintain their shape and prevents excess uptake of ____

cellulose fibers

the cell wall is made of ___ and can have multiple layers

extracellular matrix (ECM)

Animal cells lack cell walls but are covered by an elaborate

glycoproteins

ECMs are made up of __ such as collagen, proteoglycans, and fibronectin

intergrins

ECM proteins bind to receptor proteins in the plasma membrane called

plasma membrane

the boundary that separates the living cell from its surroundings, exhibits selective permeability allowing some substances to cross it more easily than others

hydrophobic

__ molecules can dissolve in the lipid bilayer and pass through the membrane rapidly

phospholipids

the most abundant lipid in the plasmid membrane

phospholipids, bilayer

___ in the plasma membrane can move within the __

fluid

membranes must be __ to work properly

cholesterol

at warm temperatures, the steroid __ restrains movement of phospholipids, while at cool temperatures it maintains fluidity by preventing tight packaging

membrane

collage of different proteins embedded in the fluid matrix of the lipid bilayer

peripheral

proteins determine most of the membrane's specific functions. ____ proteins are bound to the surface of the membrane

intergral

proteins determine most of the membrane's specific functions. ___ proteins penetrate the hydrophobic core

transmembrane proteins

Integral proteins that span the membrane

non polar, alpha helices

the hydrophobic regions of an integral protein consist of one or more stretches of __ amino acids, coiled into __ that pass through the membrane

transport proteins

allow passage of hydrophilic substances across the membrane

channel proteins

some transport proteins known as __ have a hydrophilic channel that certain molecules or ions can use as a tunnel to cross the membrane

aquaporins

channel proteins called ___ facilitate the diffusion/passage of water across a selectively permeable membrane

carrier proteins

transport proteins that undergo subtle change in shape that translocate the solute binding site across the membrane

diffusion

the tendency for molecules to spread out evenly into the available space, and is a form of passive transport

dynamic equilibrium

equal concentration, equal number of molecules move each direction

concentration gradient

substances diffuse down their ___ which requires no energy

osmosis

diffusion of water across a selectively permeable membrane

lower, higher

Water diffuses across a membrane from the region of ______ solute concentration to the region of ______ solute concentration

tonicity

the ability of a solution to cause a cell to gain or lose water

iso

-tonic solution is one in which solute concentration is the same as that inside the cell, no net water movement across the plasma membrane (non-plant cells)

hyper

__ -tonic solution is one in which solute concentration is greater than that inside the cell, cell loses water

hypo

__ -tonic solution is one in which solute concentration is less than that inside the cell, cell gains water (plant cells)

osmoregulation

the control of water balance

turgid

plant cells in hypotonic solutions swell and become

flaccid

plant cells in isotonic solutions have no net movement of water into the cell making the cell

facilitated diffusion

passive transport aided by proteins, transport proteins speed the passive movement of molecules across the plasma membrane

ion channels

open or close in response to a stimulus (gated channels)

active

__ transport uses energy to in the form of ATP to move solutes/substances against their concentration gradients

active transport

allows cells to maintain concentration gradients that differ from their surroundings

sodium-potassium pump

example of an active transport system, major electrogenic pump of animal cells

membrane potential

the voltage difference across a membrane

voltage

created by differences in the distribution of positive and negative ions across a membrane

proton pump

the main electrogenic pump of plants, fungi, and bacteria

electrogenic pump

a transport protein that generates voltage across a membrane

cotransport

occurs when active transport of a solute indirectly drives transport of other solutes

bulk transport

requires energy, occurs by exocytosis and endocytosis and moves larger molecules across the membrane

vesicles

large molecules cross the membrane in bulk via

exocytosis

out of the cell

endocytosis

into the cell, three types

phagocytosis

solid, cellular eating, cell engulfs a particle in a vacuole

pinocytosis

liquid, cellular drinking, extracellular fluid is gulped into tiny vesicles

receptor-mediated endocytosis

binding of a ligand to a receptor to trigger vesicle formation

metabolic

__pathways begin with a specific molecule and ends with a product, each step is catalyzed by a specific enzyme

catabolic

___ pathways release energy by breaking down complex molecules into simple molecules

anabolic

__ pathways consume energy to build complex molecules from simpler ones

bioenergetics

the study of how organisms manage their energy resources

energy

the capacity to cause change/do work

kinetic energy

energy of motion, heat/thermal energy

potential energy

energy that matter possesses because of its location or structure

chemical energy

potential energy available for release in a chemical reaction

thermodynamics

the study of energy transformations

closed system

a__ is isolated from its surroundings, reach equilibrium and then do no work

open system

energy and matter can be transferred between the system and its surroundings (life), cells are not in equilibrium, experience a constant flow of materials

first law of thermodynamics

the principle of conservation of energy

created, destroyed

energy can be transferred/transformed, but it cannot be __ or __

second law of thermodynamics

during every energy transfer or transformation, some energy is unusable and is often lost as heat

entropy

every energy transfer or transformation increases the ___ or disorder of the universe

negative, increase

only processes with a __ delta G are spontaneous, occur without energy input, and __ the stability of a system