Bootcamp.com - Cells and Organelles

what are the three main components in a cell membrane?

phospholipids; cholesterol; proteins

what is the structure of a phospholipid?

glycerol backbone, two fatty acid tails, and a hydrophilic phosphate group

what are the two classes of membrane proteins?

integral; peripheral

_____ membrane proteins are embedded in the core of the plasma membrane

integral

many integral proteins are _____ proteins, meaning they extend all the way through the membrane

transmembrane

integral/transmembrane proteins may function in cell _____, but most tend to transport _____ molecules across the cell membrane

signaling; large, polar (hydrophilic)

_____ membrane proteins do not extend through the entire bilayer

peripheral

what are the three types of peripheral proteins?

receptors; adhesion proteins; recognition proteins

recognition proteins are also known as _____

glycoproteins

ligands that bind to a receptor protein and activate its response are called _______

agonists

ligands that bind to a receptor and prevent it from activating are called _______

antagonists

what are the three main factors that affect membrane fluidity?

temperature; cholesterol; the degree of phospholipid tail unsaturation

saturated fatty acids have the _______ possible number of hydrogens at each carbon, which gives them a _______ shape

highest; straight

unsaturated fatty acids contain one or more _______

double bonds

_____ particles can travel directly across the phospholipid bilayer via simple diffusion

small, uncharged, non-polar (hydrophobic)

simple diffusion is the flow of substances _____ their concentration gradient in a _____ consuming process

down; non-energy

_____ does not utilize proteins to help particles across the membrane

simple diffusion

osmosis is a type of _____

simple diffusion

Water is a _____ molecule that can cross the cell membrane via osmosis because it is _____

polar (hydrophilic) ; small

_____ molecules cannot travel directly across the bilayer

large, hydrophilic

_____ describes how large, hydrophilic molecules travel across the bilayer by transmembrane proteins

facilitated transport

what are the three main types of facilitated transport (direction)?

uniport; symport; antiport

_____ move 1 molecule in 1 direction

uniporters

_____ move 2 molecules in the same (1) direction

symporters

_____ move 2 molecules in opposite (2) directions

antiporters

what are the two classes of transmembrane proteins involved with facilitated transport?

channel; carrier

_____ proteins face both the extracellular and intracellular environments of the cell

channel

channel proteins are like tunnels for many _____

small, polar molecules and ions

_____ diffusion describes a type of facilitated transport of particles down their concentration gradient through a _____ protein

passive; channel

porins and ion channels are membrane proteins that aid _____ diffusion

passive

what are aquaporins?

particular type of porin that allows water to flow more rapidly than is possible through simple diffusion alone

_____ change their shape to facilitate the movement of molecules through the protein.

carrier proteins

_____ occurs when particles travel against their concentration gradient, which requires an energy input

active transport

active transport tends to rely upon _____ proteins

carrier

what are the two types of active transport?

primary; secondary

_____ active transport uses the energy released from ATP hydrolysis

primary

the Na+/K+ pump is a form of _____ active transport

primary

the Na+/K+ pump moves _____ out of the cell and _____ into the cell with the hydrolysis of 1 ATP

3 Na+; 2 K+

secondary active transport depends on _____ to generate free energy in the form of a concentration gradient

primary active transport

_____ active transport uses free energy to pump other molecules against their concentration gradient

secondary

_____ is bulk transport of large, polar (hydrophilic) molecules

cytosis

what are the two types of cytosis?

endocytosis (in the cell) and exocytosis (out of the cell)

_____ is a type of endocytosis where a cell engulfs undissolved materials

phagocytosis

(cellular eating)

phagocytosis forms _____

vacuoles (phagosomes)

_____ is a type of endocytosis where a cell engulfs dissolved materials

pinocytosis

(cellular drinking)

pinocytosis forms _____

vesicles

receptor-mediated endocytosis forms ______

vesicles

what is exocytosis?

process by which materials exit the cell (opposite of endocytosis)

organelles are enclosed by a _____

phospholipid bilayer

membrane-bound organelles are predominately associated with which cell type?

eukaryotes

the _____ is the aqueous intracellular fluid

cytosol

the _____ is everything within the cell (fluid and organelles)

cytoplasm

what is the nucleus?

a membrane-enclosed organelle that contains most of a eukaryotic cell's genetic material

do prokaryotes have a nucleus?

no - they have a nucleoid

the nucleus contains an aqueous _____

nucleoplasm

the nucleus has an inner and outer membrane, called the _____

nuclear envelope

what is the space between the inner and outer nuclear membranes?

perinuclear space

the _____ is a dense and fibrous network of proteins associated with the inner membrane of the nuclear envelope

nuclear lamina

the nuclear lamina is made of _____

intermediate filaments

_____ are a type of intermediate filament that make up the nuclear lamina

lamins

the _____ functions to provide structural support to the nucleus; regulate DNA organization, DNA replication, and cell division

nuclear lamina

the nuclear envelope has holes called _____

nuclear pores

the _____ is a dense region in the nucleus, associated with ribosomal subunit assembly

nucleolus

is the nucleolus an organelle?

no - it is not membrane bound

ribosomal subunits contain _____ and _____

ribosomal ribonucleic acid (rRNA); proteins

eukaryotic ribosomal subunits are made in the _______ and assembled in the _______

nucleus; cytosol

what do ribosomes do?

function in the synthesis of proteins

(translation)

what is the structure of a eukaryotic ribosome?

60S + 40S = 80S

what is the structure of a prokaryotic ribosome?

50S + 30S = 70S

where are ribosomes found?

freely in the cytosol or attached to the rough ER

_____ ribosomes tend to make proteins that function within the cytosol of the cell

free

ribosomes that bind to the rough ER will synthesize proteins _____

into the rough ER lumen

the rough ER is continuous with the _____, which means the ER lumen is continuous with the _____

outer nuclear membrane; perinuclear space

what happens to proteins inside the rough ER?

they are manipulated

what is a common manipulation for proteins in the rough ER?

glycosylation to make glycoproteins

what are the two fates of proteins that enter the lumen of the rough ER?

become a part of the cell membrane; exocytosis

the _____ synthesizes lipids and steroid hormones for export

smooth ER

in some cells (ex: liver), the _____ functions in the breakdown of toxins and drugs

smooth ER

the _____ ER is not covered by ribosomes

smooth

the smooth ER is usually not attached to the _____

outer nuclear membrane

ERs send vesicles to the _____

cis-face of the Golgi

vesicles travel from the _____ to _____ of the Golgi, and the vesicle contents are manipulated along the way

cis-face; trans-face

what is the main function of the Golgi apparatus?

directing molecules to their correct locations

which organelles break down nutrients/bacteria/cell debris?

lysosomes

lysosomes receive vesicles containing digestive enzymes from the _____

Golgi apparatus

intracellular breakdown of unneeded/defective cellular components is called _____

autophagy

lysosomes function in _____ when they release their contents into the cell

apoptosis

which cells have vacuoles?

all plants and fungus; some animal, protist, bacteria

what are the types of vacuoles?

transport; food; central; storage; contractile

_____ vacuoles move materials from organelle to organelle or from organelles to the plasma membrane

transport

_____ vacuoles are temporary food holders that eventually merge with lysosomes for digestion

food

central vacuoles have a _____ and exert _____ when filled to maintain plant cell rigidity

tonoplast; turgor

_____ vacuoles (in plants) act similarly to lysosomes and storage vacuoles

central

_____ vacuoles tend to store starches, pigments, and toxic substances

storage

_____ vacuoles collect and pump excess water out of single-celled organisms

contractile

contractile vacuole use _____ transport

active

what is the endomembrane system?

group of organelles/membranes that work together to modify, package, and transport proteins and lipids that are entering/exiting a cell

what are the components of the endomembrane system?

nucleus/nuclear envelope, rough and smooth ERs, Golgi apparatus, lysosomes, vacuoles, and cell membrane

_____ break down fatty acids and some amino acids; also involved with detoxification

peroxisomes

alcohol detoxification occurs in the _____ of liver cells

peroxisomes and smooth ER