Chapter 4, General Features of Cells Flashcards
The Cell Theory (3 parts)
1.) Cells are fundamental unit of life
2.) All organisms are composed of cells
3.) All cells come from preexisting cells
As cell _________ in volume, the surface area _________
increase, increases
The surface area increases at a _________ rate
lower
The cell’s volume determines its…
metabolic activities
The cell’s surface area determines its…
rate of transport into and out of the cell
As the cell grows, the metabolic activity…causing the cell to…
increases at a faster rate than surface area, so it must split to keep things balanced
Magnification…
makes something larger
Resolution…
makes something clearer
minimum distance between two objects
ability to observe 2 objects as distinct
Microscopes increase both…
magnification and resolution
Light Microscope
- 430 x
- resolving power: 200 nm
- uses light passing through the sample to observe objects
Transmission Electron Microscope
- 50 million x
- resolving power = 0.2 nm
- uses electron beam passing through sample to view objects
- cell must be killed and stained with heavy metals to block/scatter electron beam, those that pass through are focused
Scanning Electron Microscope
- 2 million x
- resolving power = 0.5 nm
- Coats surface of sample with heavy metal stains, uses electron beam to scan surface
- obtains more 3D view of object
Domains containing Prokaryotic cells…
Bacteria, Archaea
Prokaryotic cells…(3)
- lack membrane-bound organelles (nucleus)
- relatively simple
- generally smaller
Prokaryotic Cells contain…
plasma membrane
cell wall
capsule
nucleoid
cytoplasm
ribosomes
flagella
Plasma Membrane (structure and function)
single membrane, regulate transport
Cell Wall (structure and function)
Peptidoglycan membrane, protection/support
Capsule (structure and function)
Polysaccharides, prection/hydration
Nucleoid (structure and function)
aqueous, hereditary/DNA
Cytoplasm (structure and function)
aqueous, biochemical reactions
Ribosomes (structure and function)
solid - RNA and proteins, protein synthesis
Flagella (structure and function)
solid - proteins, movement
Domains containing Eukaryotic Cells
Protista, Plantae, Animalia, Fungi
Eukaryotic cells…
- contain membrane bound organelles
- are complex with many organelles
- are larger in size
Cytoplasm is _______ mixture
aqueous
Cytoplasm contain many…
proteins
Many protein are…
enzymes
Enzymes control…
a host of reactions
Reactions in cytoplasm are often…
the first reactions in important metabolic pathways
The cytoskeleton is made up of…
series of fibrous organelles
The purpose of cytoskeleton is to…
provide internal skeleton to cells
Three types of fibers that make up cytoskeleton constructed from
many protein monomers
Microtubules made up of
Tubulin
Microtubules are
largest long hollow tubes contributing to cytoskeleton
Microtubules have two different
charged ends
_________ and _________ help microtubules grow and shrink
Centrioles and Basal Bodies
Function of microtubules are to…
form cellular roads which vesicles and chromosomes move using molecular motors
Molecular motors in microtubules are…
Kinesin
Motor protein travels along microtubule from ___ end to ____ end
negative to positive
Microtubules form _____ and _____ for cellular locomotion
cilia, flagella
Microtubules form the ______ ________
Miotic Spindle
The miotic spindle …
moves chromosomes during nuclear division (mitosis)
Intermediate filaments are made of…
thing rods of keratin
There are ________ different types of intermediate filaments
over 50
Intermediate filaments do not have
charged ends
Intermediate filaments are more ____ than any other element of cytoskeleton
stable
Functions of intermediate filament (3)
- maintain cellular shape
- provide mechanical strength
- line inside of nuclear membrane to anchor nuclear pores
Microfilaments are the _____ of the three in the cytoskeleton
smallest
Microfilaments made out of
thin rods of actin
Microfilaments can exist as…
single filaments
in bundles
in networks
Functions of microfilaments (4)…
- cellular movement (muscle contraction, cytoplasmic streaming, pseudopod formation)
- cytoplasmic division (cytokinesis) to divide cell into two daughter cells following mitosis and meiosis
- occur near plasma membrane and anchor other proteins
- support plasma membrane and provide shape and strength to cell
All provide shape and strength to cell, but _______ most important
intermediate filaments
The nucleus is a ____ ______ structure
double membrane (lipid bilayer)
Function of nucleus is to …
store DNA
Nuclear membrane has thousands of nuclear pores which…
regulate transport between nucleus and cytoplasm
Pores are surrounded by complex of…
8 large protein granules
Proteins targeted for nucleus have a short peptide _________ _________ ________
Nuclear Localization Signal
Nucleolus consists of…
genes which code for ribosomal RNA
rRNAs are needed for …
Ribosome contruction
_______ have no membrane so technically are not organelle
ribosome
Function of ribosomes
proteins synthesis
Location of ribosomes (3)
- floating in cytoplasm
- attached to ER
- inside mitochondria/cytoplasm
Endomembrane system
group of functionally interrelated organelles
Endomembrane consists of (8)
nuclear envelope, ER, golgi apparatus, lysosomes, peroxisomes, vacuoles, plasma membrane, vesicles which shutter material between these
Endoplasmic Reticulum composed of…
single membrane surrounded by central lumen
ER consists of ____ and ____ sacs
folds, flattened
ER composes ____% of cell’s total volume
10
Because of ER’s _____, many times greater than Plasma Membrane
folds
The lumen is the…
hollow part of ER
Rough ER has…
ribosomes throughout
Ribosomes…
synthesize proteins which are then transported into lumen of ER, segregating them from cytoplasm
Proteins in rough ER can be _______ _________ to alter their function
chemically modified
Proteins can also be tagged with a ______ ________ _________ to mark them for delivery to various organelles by way of vesicles
short peptide signal (like an address)
Some of these proteins have an oligosaccharide chain attached and from _________
glycoproteins
Function of rough ER
synthesize/modify glycoproteins, membrane-bound proteins, and proteins destined for various organelles
Smooth ER does not have…
ribosomes
Smooth ER is more _____ than flattened sacs
tubular
Smooth ER is _____ with sections of rough ER
continuous
Functions of smooth ER (3)
- detoxify various poisons
- contains enzymes necessary for and metabolism
- synthesize phospholipids for membrane, and other lipids like steroid hormones
Smooth ER modifies poisons so that they are…
more polar and easier to excrete from cell
Smooth ER has enzymes necessary for ______ and ______ metabolism
glycogen and calcium
Structure of Golgi Apparatus
flattened sacs (single membrane)
_________ transport proteins from ER to golgi
Vesicles
proteins travel from ____ to medial to ____ regions of golgi
cis, medial, trans
_____ come from smooth ER
lipids
_____ come from rough ER
proteins
Golgi adds/modifies…
carbohydrate portion of Glycoproteins
Proteolysis
cuts large proteins into smaller, functional proteins
Secretion packages materials into _______ _________ to be…
secretory vesicles, released from cell
Golgi function: _________, _______, and __________ proteins and lipids before being transported to cellular/extracellular destinations
concentrate, package, sort
Lysosome structure
large vesicle with glycoproteins surrounded by single membrane
Lysosomes contain _________ enzymes
digestive
Lysosome function
Digestion via hydrolytic reactions
Primary Lysosomes
formed by vesicles containing hydrolytic enzymes forming from golgi
Secondary Lysosome
formed by function of primary lysosome and food vacuole
another name for food vacuole
phagosome
Function of vacuole (2)
- storage of food or waste materials
- maintain turgor pressure
Contractile vacuole
protists use to excrete water
in contractile vacuoles water…
diffuses in, vacuole contracts, forcing water out via pores
Function of microbodies
contain enzymes for specific functions
2 subclasses on microbodies
- peroxisomes
- glyoxysomes
Function of peroxisomes
contain catalase to degrade hydrogen peroxide
Hydrogen peroxide formed…
as byproduct of many types of reactions, high levels is toxic
Peroxisomes are synthesized…
as vesicles from ER
Glyoxysomes contain…
enzymes for specific reactions
Glyoxysomes primarily found in
plant seeds
Function of glyoxysomes
covert stored lipids into carbs for growth
Plasma membrane part of the ______ system
endomembrane
Plasma Membrane _______ cell and…
surrounds, divides it from external environment
Plasma Membrane Functions (3)
- Membrane Transport (everything in and out must pass through membrane by protein transporters)
- Cell Signaling (uses hormones to communicate to each other and external environment)
- Cell Adhesion (cell need way to hold cells together, proteins help fulfill this role
List of Semiautonomous Organelles
- mitochondrial
- chloroplast
mitochondria involved in…
cellular respiration
chloroplast involved in…
photosynthesis
Mitochondria and chloroplasts can…
divide independently of the cell
Mitochondria and chloroplast also contain their own
DNA and ribosomes
Structure of mitochondria
double membrane, two spaces
Function of mitochondria
convert energy in organic molecules into ATP
Cellular Respiration begins in the _________ with ________
cytoplasm, Glycolysis
It continues in the mitochondria with…. and …..
krebs cycle, electron transport
The end product of cellular respiration is _______
ATP
ATP is a modified ________ which has high energy content
nucleotide
ATP used to do…
most types of cellular work
Plastids found in
plants and algae
Plastids include ________
chloroplasts
Plastids structure
three membrane
Three membranes of plastids include
outer, innter, thylakoid (innermost)
Function of plastids
photosynthesis
Chloroplasts contain ____________ _______, embedded within internal stacks of membranes
photosynthetic pigments
Internal stacks of membranes in chloroplasts are called
thylakoids
Thylakoid membranes distinctive because they are only…
10% phospholipid content
Fluid surrounded thylakoids is…
stroma
Chromoplasts are plastids but not…
semi-autonomous
Chromoplasts function
produce and store various carotenoid pigments
Chromoplasts pigments are the colors…
red, orange, yellow
Color in chromoplasts helps to..
attract pollinators for pollination of seeds
Leukoplasts are plastids but not…
semi-autonomous
function of leukoplasts
stores food (starch, fats)
Endosymbiont Theory tries to explain origin of
Mitochondria, Chloroplasts, Eukaryotic Cells
Starting point of Endosymbiont Theory is _________ cell, some of them having _________ ___________ and others __________
Prokaryotic, aerobic respiration, photosynthesis
The engulfment stage is when…
large prokaryotic cells engulfed smaller ones but did not digest them
Over time these cells became ___________ and ___________ with a _____ membrane
mitochondria, chloroplasts, double membrane
Supported evidence is that these are only organelles to…(3)
- contain own DNA
- contain own ribosomes
- both double membraned
Many structures are _______ by the cell and _________ by the cell
produced, secreted
Extracellular Structures includes the cell walls of…(3)
Plants, Fungi, Bacteria
Extracellular structures also includes the _________ _________
extracellular matrix
Plant cell wall structure
Thin mat of cellulose fibers
Plant cell wall function (3)
- support cell
- limit volume of cell and maintain turgor pressure
- forms barrier to prevent infection by fungi and bacteria
Extracellular Matrix structure
interwoven mat of fibrous proteins
Fibrous proteins in extracellular matrix include
collagen, glycoproteins (proteoglycans), proteins which link the others together
Function of extracellular matrix
help connect adjacent cells together
Each organelle has own set of _______ that carry out most functions
proteins
All proteins made in the same place, in __________ in the cytoplasm
ribosomes
Proteins synthesized on the
ribosomes in the cytoplasm
Many proteins stay in the _______ to perform their roles
cytoplasm
Other proteins are destined for an _______ and travel there after synthesis
organelle
Two kinds of sorting are
- cotranslational sorting
- post-translational sorting
Cotranslational sorting is when…
proteins take first step in being sorted to organelles while the are being translated
The first ___-___ amino acids are nonpolar and form an ER Signal Sequence
12-20
The first amino acids made are the
sorting ones thats tell the protein where to go, so as they travel and know where to go they can make actual protein
Special protein that binds to the signal sequence is the
SRP (signal recognition protein)
After SRP binds to signal sequence…
it drags ribosome to ER, and attaches to SRP receptor
After SRP docks with receptor…
protein chain threaded through channel protein embedded in ER
Once protein is threaded through, ends up in the ______ of the ER
lumen
Translation is continued and then the…
signal protein is removed
In cotranslational sorting, they are possibly modified and then…
packaged into vesicles for transport to destination of organelle
New singals put on proteins after…
they have reached destinations, because always going to new destinations
Vesicles have specific protein receptors embedded in membrane to…
help vesicle fuse with proper target organlle
Post Translational Sorting is when…
proteins synthesized on ribosomes and then sorted after they are made
The first 12-20 amino acids on Post Translational Sorting act as…
Transit sequences or sorting signals, tells them their destination
The sequence is bound and transported by _______ to a receptor protein on outer membrane or organelle
chaperones
Once bound the protein is…
threaded through channel protein
Once it is in organlle…
signal sequence is removed and the protein carries out its function
Nuclear proteins are unique becuse…
their signal/transit sequences are not removed
Nucleus is constantly dividing meaning that…
singal not removed because proteins must continually be re-delivered to nucleus
