Tour of the cell
In cell theory, which states that cells are the fundamental units of life and that all living things are made of cells, a minor caveat is included. What for?
Viruses which we only consider living when they are infecting a cell
Define Magnification
the ratio of the image to the real size of the specimen
Define Resolution
the clarity of your image
Define Contrast in relation to microscopes
the visibility of different parts of the sample
What is the main commonality between all light microscopy techniques?
The use of bent or refracted light to enhance magnification
Which three light microscopy techniques are create digital images?
Confocal microscopy, Deconvolution, Super resolution
Is the brightfield light microscopy technique ideal for studying living cells? Why or why not?
No, the contrast is not high and in order to increase it one must stain their samples (which involves fixing them in place which kills them).
Which light microscopy technique is good for living, unpigmented cells?
Phase-contrast
What are the two types of electron microscopy and what are they used for?
SEM (Scanning electron microscopy) and TEM (transmission electron microscopy). Used for studying subcellular structures
What is the key tool used for cell fractionation and very generally why do we use it?
The centrifuge, used to break down cells into their individual components
Cells are _____% water. The rest we call ____ ________, which is mostly proteins.
90, dry weight
Eukaryotic cells have cytoplasm between their plasma membrane and their nucleus, true or false?
true
Generally, eukaryotic cells are bigger than prokaryotic cells by a ratio of ____
10:1
Within ____________ cells there are still differences between kingdoms. Some features unique to plant cells are chloroplasts, large, central vacuoles, cell walls, and _________________ (holes between cells for communication).
eukaryotic, plasmodesmata
Two of the three domains of life (_________ and __________) are composed entirely of prokaryotic cells
Archaea and Bacteria
Prokaryotic cells have easier access to their own DNA. What are the pros and cons to this system?
Faster replication of DNA but increased chances of producing mistakes in translation
To keep prokaryotic cells safe they have a cell wall uniquely containing ______________
peptidoglycan
The nucleus houses the cell's genes, sections of chromosomes composed of DNA ordered into packages called ______________
chromatins
The nucleus had a double membrane called the ____________ ____________ which has pores to allow passage of material
Nuclear envelope
Inside the nucleus is a site called the nucleolus where ___________is carried out by rRNA
synthesis
Briefly and simply describe what ribosomes are made of and what locations you'd find them at.
Two rRNA particles found in the cytosol and the surface of the ER
What are the six components of the endomembrane system and of those which components are physically connected?
*These two are the only components physically continuously connected
The rough ER synthesizes what?
glycoproteins and proteins
The smooth ER functions to synthesize_________, metabolize_______, detoxify _________ and ____________, and store ______________ ions
lipids, carbs, drugs and poisons, Calcium
The golgi apparatus is made of flattened membrane sacs called ____________
cisternae
The membrane of the golgi apparatus has the ___________ direction of the plasma membrane. Why?
inverse, so that when its vesicles merge with the plasma membrane they are right side out (proteins, extracellular components, glycoproteins must all be facing the correct direction from the cell)
Lysosomes are double membrane compartments that transport ___________ ___________ to digest proteins, fats and polysaccharides through hydrolysis
hydrolytic enzymes
Lysosomes are also responsible for breaking down and recycling old or damaged organelles through ___________.
autophagy
Vacuoles preform a diverse array of functions, true or false?
True
Contractile vacuoles pump excess water out of cells in many freshwater ___________
protists
food vacuoles are created how?
via phagocytosis
What are peroxisomes?
oxidative organelles
What is endosymbiotic theory?
The theory that mitochondria and chloroplasts were at one point separate organisms that were engulfed by a eukaryotic cell and evolved to live in symbiosis with it
endosymbiotic theory and is evidenced how?
free ribosomes and circular DNA molecules in addition to the prokaryotic-like mechanisms that the organelles use to grow and reproduce independently inside cells
Mitochondria have two membranes. The inner one has lots of fold called cristae. What purpose does this serve?
They increase surface area for enzymes that synthesize ATP
Inside chloroplast's second membrane is the soluble compartment called _________ which house thylakoid membranes that form internal compartments called ________ __________ where chlorophyll is held
stroma, thylakoid lumen
We have not reached a consensus about how peroxisomes are related to other organelles but we do know they produce ____________ _____________ and convert it into__________.
hydrogen peroxide, water
The cytoskeleton is a mesh of fibers that extends throughout the cytoplasm. What does it do?
maintain the shape of the cell, anchor organelles and aid in the transport of vesicles
What are three main structures to the cytoskeleton?
Rank the three main cytoskeleton structures from smallest to biggest.
Microfilaments, intermediate filaments, microtubules
What protein are microtubules made of?
1. Actin and myosin
2. dynein
3. tubulin
3. tubulin
What protein are Microfilaments made of?
1. Actin and myosin
2. keratin
3. dynein
1. Actin and myosin
Intermediate filaments are composed of different proteins such as keratin and function in supporting cell shape and anchoring organelles, true or false?
True!
Which kingdoms of life have cell walls?
Prokaryotes, plants, fungi and some protists
What are the three layers to the plant cell wall?
the middle lamella (between plant cells), the primary cell wall and the secondary cell wall (in some cells)
What are the channels in cell walls called?
Plasmodesmata
Instead of a cell wall animal cells have an elaborate _____________ ______________ _____________
Extracellular matrix (ECM)
ECM that functions in ...(4)
support, movement, adhesion and regulation
The ECM binds to receptors in the plasma membrane called___________ which communicate through hormones to regulate cell behavior.
integrins