Organelles Flashcards
All organisms are made of ______
cells
The cell is the ______ collection of matter that can live
simplest
Cell structure is correlated to ______
function
All cells are ______ by their descent from earlier cells
related
Though usually too small to be seen by the unaided eye, cells can be _____
complex
Scientists use ______ to visualize cells too small to see with the naked eye
microscopes
The quality of an image depends on ____, ______, and _______
magnification, resolution, and contrast
The quality of an image depends on
magnification
visible differences in parts of the sample
contrast
the measure of the clarity of the image, or the minimum distance of two distinguishable points
resolution
Resolution is _____ related to the wavelength used to visualize (Light, electron)
inversely
In a ____ microscope, visible light passes through a specimen and then through glass lenses, which magnify the image
light
LMs can magnify effectively to about _____ times the size of the actual specimen
1,000
Various techniques enhance ______ and enable cell components to be stained or labeled
contrast
Most subcellular structures, including organelles (membrane-enclosed compartments), are too _____ to be resolved by an LM
small
Two basic types of electron microscopes (EMs) are used to study ______ structures
sub cellular
Scanning electron microscopes (SEMs) focus a beam of electrons ____ __ _______ of a specimen, providing images that look 3-D
onto the surface
Surface covered with a film of ____ in SEMs
gold
Transmission electron microscopes (TEMs) focus a beam of electrons ______ __ ________
through a specimen
TEMs are used mainly to study the ____ structure of cells
internal
Cell fractionation takes cells ____ and ______ the major organelles from one another
apart; separates
________ separate organelles into their component parts
ultracentrifuge
Cell fractionation enables scientists to determine the ______ of organelles
functions
_______ and ______ help correlate cell function with structure
biochemistry; cytology
The basic structural and functional unit of every organism is one of two types of cells: ______ or ________
eukaryotic; prokaryotic
Only organisms of the domains Bacteria and Archaea consist of ________ cells
prokaryotic
Protists, fungi, animals, and plants all consist of ________ cells
eukaryotic
Both prokaryotic and eukaryotic cells have
plasma membrane, cytosol, chromosomes, ribosomes
a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell
plasma membrane
The general structure of a biological membrane is a _____ layer of phospholipids
double
semifluid interior substance
cytosol
carry genes
chromosomes
make proteins
ribosomes
No nucleus
DNA in an unbound region called the nucleoid
No membrane-bound organelles
Cytoplasm bound by the plasma membrane
the basic characteristics of prokaryotic cells
DNA in a nucleus that is bounded by a membranous nuclear envelope
Membrane-bound organelles
Cytoplasm in the region between the plasma membrane and nucleus
the basic characteristics of eukaryotic cells
eukaryotic cells are generally much _____ than prokaryotic cells
larger
The surface area to volume ratio is ____ in a cell
critical
As the surface area increases by a factor of n2, the ______ increases by a factor of n3
volume
small cells have a greater _____ ___ relative to large cells
surface area
nucleus, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, plasma membrane are all organelles of the _________ system
endomembrane
Mitochondria
Chloroplasts
Peroxisomes are all organelles of the ______ group
energy conversion
The nucleus contains most of the cell’s ____ and is usually the most conspicuous organelle
genes
The nuclear envelope encloses the _____, separating it from the cytoplasm
nucleus
The nuclear membrane is a _____ membrane; each membrane consists of a lipid bilayer
double
Pores regulate the ____/_____ of molecules from the nucleus
entry/exit
The shape of the nucleus is maintained by the nuclear _____, which is composed of protein filaments
lamina
In the nucleus, DNA and proteins form genetic material called _____
chromatin
Chromatin ________ to form discrete chromosomes
condenses
The nucleolus is located within the nucleus and is the site of ________ ___synthesis
ribosomal RNA
responsible for the conversion of genetic material to protein
ribosomes
Ribosomes are particles made of _____ and _____
rRNA; protein
In the cytosol, ____ ribosomes generally make proteins for use in the cytosol
free
On the outside of the endoplasmic reticulum or the nuclear envelope, ______ ribosomes generally make proteins for transport through a membrane
bound
The _________ _______ accounts for more than half of the total membrane in many eukaryotic cells
endoplasmic reticulum
The ER membrane is ______ with the nuclear envelope
continuous
What are the 2 distinct regions of the ER?
rough ER and smooth ER
lacks ribosomes Synthesizes lipids Metabolizes carbohydrates Detoxifies poison Stores calcium
smooth ER
Has bound ribosomes, which secrete glycoproteins
Distributes transport vesicles, proteins surrounded by membranes
Is a membrane factory for the cell
rough ER
proteins covalently bonded to carbohydrates
glycoproteins
The Golgi apparatus consists of flattened membranous sacs called _______
cisternae
Modifies products of the ER
Manufactures certain macromolecules
Sorts and packages materials into transport vesicles
golgi apparatus
A _______ is a membranous sac of hydrolytic enzymes that can digest macromolecules
lysosome
Lysosomal enzymes can hydrolyze
proteins
fats
polysaccharides
nucleic acids
Some types of cell can engulf another cell by _________; this forms a food vacuole
phagocytosis
A lysosome fuses with the ____ _____ and digests the molecules
food vacuole
Lysosomes also use enzymes to recycle the cell’s own organelles and macromolecules, a process called ______
autophagy
A plant cell or fungal cell may have one or several _______
vacuoles
____ vacuoles are formed by phagocytosis
food
_______ vacuoles, found in many freshwater protists, pump excess water out of cells
contractile
_____ vacuoles, found in many mature plant cells, hold organic compounds and water
central
Mitochondria are the sites of ______ ________, a metabolic process that generates ATP
cellular respiration
Chloroplasts, found in plants and algae, are the sites of ________
photosynthesis
Peroxisomes are _____ organelles
oxidative
mitochondria and chloroplasts….
Are not part of the endomembrane system
Have a double membrane
Have proteins made by free ribosomes
Contain their own DNA
_______ are nearly in all eukaryotic cells
mitochondria
The inner membrane creates two compartments which are the
intermembrane space and mitochondrial matrix
Some metabolic steps of cellular respiration are catalyzed in the _______ _____
mitochondrial matrix
Cristae present a large ______ ____ for enzymes that synthesize ATP
surface area
The chloroplast is a member of a family of organelles called _____
plastids
Chloroplasts contain the green pigment ________, as well as enzymes and other molecules that function in photosynthesis
chlorophyll
Chloroplasts are found in leaves and other _____ organs of plants and in algae
green
Chloroplast structure includes
thylakoids and stroma
membranous sacs, stacked to form a granum
thylakoids
the internal fluid
stroma
_______ are specialized metabolic compartments bounded by a single membrane
peroxisomes
is used to break down different types of molecules
oxygen
Peroxisomes produce ______ ______
hydrogen peroxide
Convert H2O2 (which is toxic) to
water
The __________ is a network of fibers extending throughout the cytoplasm
cytoskeleton
_________ organizes the cell’s structures and activities, anchoring many organelles
cytoskeleton
What are the 3 types of structures that make up the cytoskeleton?
microtubules,microfilaments, and intermediate filaments
the functions of ______ include Shaping the cell,
Guiding movement of organelles, and
Separating chromosomes during cell division
microtubules
the thickest of the three components of the cytoskeleton
microtubules
The ________ is a “microtubule-organizing center”
centrosome
__________ control the beating of cilia and flagella, locomotor appendages of some cells
microtubules
Cilia and flagella _____ in their beating patterns
differ
A core of microtubules sheathed by the plasma membrane
A basal body that anchors the cilium or flagellum
A motor protein called dynein, which drives the bending movements of a cilium or flagellum
are all things ______ by cilia and flagella
shared
_____ arms alternately grab, move, and release the outer microtubules
dynein
also called actin filaments
the thinnest components
microfilaments
The structural role of _______ is to bear tension, resisting pulling forces within the cell
microfilaments
fibers with diameters in a middle range
They support cell shape and fix organelles in place
intermediate filaments
The extracellular structures are _____, _____, and ______
Cell walls of plants
The extracellular matrix (ECM) of animal cells
Intercellular junctions
distinguishes plant cells from animal cells
Prokaryotes, fungi, and some protists also have this
plant cell wall
Protects the plant cell, maintains its shape, and prevents excessive uptake of water
Made of cellulose fibers embedded in other polysaccharides and protein
plant cell wall
what are the 3 layers of plant cell walls?
primary, middle lamella, and secondary cell wall
__________ are channels between adjacent plant cells
Plasmodesmata
____ _____ lack cell walls but are covered by an elaborate extracellular matrix (ECM)
animal cells
ECM proteins bind to receptor proteins in the plasma membrane called _____
integrins
Functions of the ECM:
Support
Adhesion
Movement
Regulation
Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact; _______ ______ facilitate this contact
Intercellular junctions
plasmodesmata, tight junctions, desmosomes, and gap auctions are all types of _______ ______
intercellular junctions
channels that perforate plant cell walls. Through these junctions, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell
plasmodesmata
membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid
tight junctions
(anchoring junctions) fasten cells together into strong sheets
desmosomes
(communicating junctions) provide cytoplasmic channels between adjacent cells
gap junctions
