EXAM 1 Flashcards
Review exam 1 content
What makes a good model eukaryote?
Genome Sequenced
Developmental Sequence known
Site and tissue specific mutagenesis possible
Expression of multiple genes can be tracked across many cells
Cell Theory
Idea that all living things are composed of cells, cells are the basic units of structure/function in living things, and new cells are produced from existing cells
Light microscope
instrument with lenses that bend visible light to magnify images of specimens.
limitation of light microscope
resolution = .20 micrometer
Resolution
ability to distinguish two subjects as separate.
Magnification
Increase an objects size by using lenses.
Detection
Ability to determine the presence of the object.
Fluorescence microscopy
chemical dyes producing color by observing specific wavelengths and emitting others that can be seen through barrier filters.
Confocal microscopy
Uses scanning laser light through a pinhole to illuminate fluorescently labeled sample.
Electron microscope
Forms an image by focusing beams of electrons onto specimens.
special preservation for cell before electron microscopy
Fixation is required first of the cell
Sliced into thin sections
why are staining techniques required for electron microscope.
Electron dense materials used to stain cells
Lot of dense = more reflective to light
Scanning electron microscopy
Images of outside surface of cell (only staining)
Transmission electron microscopy
Images internal structures of cell (only sectioning)
Flow cytometry
uses fluorescent labels to measure specific levels of biomolecules/ions and sort cells base on expression of the levels of fluorescent data
Phase contrast microscope
light microscope that enhances contrast
most useful in examining living unstained cells
what are the small carbons molecules that form the cell
sugars
amino acids
nucleotides
fatty acids
Larger units of the carbon molecules
Polysaccharides from sugars
Fats, lipids, and membranes from fatty acids
Proteins from amino acids
Nucleic acids from nucleotides
What are polymers?
Linkage of multiple monomers
What reactions form monomers?
Dehydration reactions = loss of water from the reacting molecule
What are carbohydrates?
Are sugar molecules made from monomers
chemical nature = polar
What is alpha sugar linkage?
Position of the OH on the C1 carbon group is below the ring
What is a beta sugar linkage?
Position of the OH on the C1 Carbon group is above the ring
What are lipids?
Fatty and oil components that are double in organic solvents and insoluble in polar solvents
What is the function of the lipid?
Apart if cell membrane and help control what goes in or out of the cell
Storage and move energy
Membrane barriers
what is the function of carbohydrates
They are use as a energy source, structural support and binding surface for the cell
What is the chemical nature of lipids?
Amphipathic
Contains both a polar (water soluble) and nonpolar (not water soluble) portions within its structure
What are phospholipids?
A type of lipid
Molecules that form the cell membrane
Function and purpose of phospholipids?
Forming permeability of the cell membrane
Preventing accumulation of fats in the liver
Removal of cholesterol in the cells
What are amino acids?
The building blocks of proteins
What are proteins?
Long chain molecules made from multiple amino acids
Chemical structure of amino acids?
Varies by the R group
What are the functions of proteins?
Build and repair body tissue
Structural support of the cell
Negatively Charged/ Acidic amino acids
Acidic = Ph level is very low (Aspartate, Glutamate)
positively charged/ Basic amino acids
Ph level is very high (histidine, Lysine, Arginine) positively charged
What are nucleotides?
Made from nucleic acids and are short term energy carriers
What is the chemical structure of nucleotides?
Base group (nitrogenous base)
Deoxyribose sugar
Phosphate group
What are nucleic acids?
Chain of nucleotides which stores genetic information for the cell
Functions of nucleotides?
Serve as basic structural for DNA or RNA
Functions of nucleic acids?
Storage and expression of genetic information within the cell
How is ATP related to nucleotides?
Nucleotides carry ATP and it is negatively charged
What is the first law of thermodynamics?
Energy cannot be destroyed or created only converted into one form to another
What is the second law of thermodynamics?
Every energy transfer or transformation increases the entropy of the universe
What is entropy?
The amount of disorder in a system
How is entropy related to cells?
Cells are highly ordered and have to perform processes to maintain that order resulting in the increase of entropy
What is spontaneous in terms of a reaction?
Reaction that happens without any supply of energy
Why are cells not isolated systems?
Able to exchange energy with their environment
What is the plasma membrane?
Combination of lipids and proteins that form a cellular boundary between the cells inside contents and the outside of the cell
What is the function of the plasma membrane?
Regulates the materials that enter or exit the cell
Protect the cell from its surrounding environment
What is the structure of the plasma membrane?
Lipid bilayer
Protein molecule
Lipid molecule
What are phospholipids?
Is it a type of lipid that has two parts
Glycerol backbone (polar)
Fatty acid tails (non polar)
Why are phospholipids amphiphilic?
They have a hydrophilic head (watering loving)
They have hydrophobic fatty acid tails (water fearing)
describe the nonpolar tails of the phospholipid membrane
(1) saturated [no c=c] tightly packed
(2) unsaturated [cis c=c] prevents tight
Why are phospholipids being amphiphilic important for cell membrane development?
Help cell membranes and surrounding organelles to be flexible and not stiff
What are sterols?
Hydrophobic carbon ringed lipid molecules
animal sterol
cholesterol
plant sterol
phytosterol
fungi sterol
ergosterol
What is the function of sterols in the plasma membrane?
Alter membrane fluidity and structure
fluid mosaic model
Structural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer
What feature allows phospholipids to self assemble into lipid bilayer membrane?
amphiphilic nature
-polar heads associate w h20 on outside
-hydrocarbon tails associate w one another on inside
What is the function of the bilayers for the cell membrane?
Acts like barrier that keeps molecules such as proteins where they needed and prevents them from moving into area they should not be at
How do we get membranes to form into spheres
edges exposed to water and fold into each other to avoid contact w water. spontaneous.
what are the two halves of the phospholipid bilayer called
leaflets
How do lipid bilayers allow lateral diffusion?
Only allows nonpolar molecules into the cell since it is amphiphilic
Molecules moving from high concentration to lower concentration region
How is a symmetric membrane converted into an asymmetric one?
When the inner and outer leaflets have different molecular structure
How might the asymmetric distribution of lipids in the plasma membrane contribute to its function?
Needed for signal transduction (transferring signal through the cell)
What are leaflets of the plasma membrane?
What are lipid rafts?
Microdomains in the cell membrane that has high concentrations of cholesterol and glycosphingolipids for signal transduction
Where are the proteins located in the cell membrane?
Are embedded in the phospholipid bilayer
types of proteins in the cell membrane?
Peripheral proteins = bound to membrane surface
Integral proteins = inserted into membrane interior (transmembrane protein)
What important functions do proteins provide to the cell membrane?
Transport of molecules
Signal transduction
Cell - cell recognition
What is a transmembrane region within a cell membrane?
Are the pores within a lipid bilayer
Formed by proteins that run across the membrane
What functions do integral membrane proteins do?
Attach the protein to a membrane
Transport molecules across the cell
Carriers through the membrane
How do phospholipids contribute to the making of liposomes?
When phospholipids are in water spherical vesicles (liposomes) assemble spontaneously
How do black membranes form?
A hole in a partition between two aqueous compartments
What is the plant cell wall?
A outer ridge semi elastic supportive and protective layer
what is the plant cell wall made of?
carbohydrates
What are the polymers of the plant cell wall?
cellulose
pectin
lignin
protein/glycoproteins
cross linking glycans
function of cellulose in the plant cell wall
Polysaccharide of glucose that forms plant’s cell walls and provides tensile strength (resistance to material breaking due to tension)
function of Pectin in the plant cell wall
Provides resistance to compression
Provides strength, flexibility to the cell wall
function of Lignin in the plant cell wall
that hardens cell walls of some vascular tissues in plants
reinforces secondary cell walls
function of protein/glycoproteins in the plant cell wall
Responsible for wall turnover
Responsible for wall remodeling
function of Cross linking Glycans in plant cell walls
Assist in folding and trafficking of proteins
What is the function of the plant cell wall?
Supports and protects interior structures and organelle of the cell
turgor pressure
the pressure that is exerted on the inside of cell walls and that is caused by the movement of water into the cell
Why is it important for the cell to produce turgor pressure?
Rigidity provides expansion during cell growth
What is the nucleus?
A double membrane structure that contains genetic material of DNA for the cell
what is the nuclear membrane
controls what goes in and out of the nucleus
What is the function of the nucleus?
Responsible for storing cells genetic material of DNA
What is a nuclear lamina?
a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope
What is the function of the nuclear lamina?
Regulates DNA replication and cell division
How does the nuclear lamina relate to the nucleus?
It provides structural support to the nucleus
What are nuclear pores?
Openings in the nuclear envelope
What are the components of nuclear poles?
Consists of proteins known as nucleoporins
What is the function of nuclear pores?
Facilitate communication between the nucleus and cytoplasm
what is a chromatin
Genetic information composed of DNA and proteins that condense to form chromosomes
highly dynamic (DNA condenses/decondenses)
What is the chromatin function?
What is the chromatin function?
What are histones and how are they formed?
Proteins that are associated with DNA in the nucleus and help condense it into a chromatin
Composed of a tail and an amino acid chain
What are the functions of histones?
Organize DNA within the cell nucleus by packaging it into compacted structures (nucleosomes)
What are nucleosomes?
DNA around a core of histone proteins
What are the structures of chromatin?
Heterochromatin
Highly condensed
DNA is resistant to gene expression
Euchromatin
Less condensed
Accessible to RNA transcription
origin of replication
Site where the replication of a DNA molecule begins,
Why is chromatin important for cell development?
Can unwind for DNA replication and transcription
What are the different modifications histones go through?
Acetylation - adding or getting rid of acetyl groups, opening the chromatin
Methylation - addition of methyl groups to histones, causing a more compacted chromatin
what are the various modifications to lysine?
- acetylate= eliminate + charge => neutral
- methylate= masks charge => “less + charge”
- phosphorylate serine = adds - charge
How do histone modifications affect/regulate the chromatin structure?
They control the access of proteins to the DNA regions resulting in regulation of chromatin structure
How does histone modification play a role in cell development?
Are responsible for gene regulation during cell development
What is the mitochondria?
The organelles that produce ATP and the main energy molecule for the cell
What are the components of the mitochondria?
Outer membrane -
Encloses the organelle
Contains many porins (channel proteins =
transmembrane protein)
Allow chemicals mitochondria needs to pass
through the organelle
Inner membrane -
Folded inner membrane
The folds of the inner membrane are called
cristae
The folds are where the reactions creating
energy take place
Cardiolipin = special type of lipid
Helps from the inner wall of the structure
Stabilizing the supramolecular structure of
large membrane proteins, like ATP synthases
Site of electron transport chain
Intermembrane space -
The space between the membranes
Regulate programmed cell death
Matrix -
Site of oxidative metabolism
Contains DNA ribosomes and other
components for expression of the
mitochondrial genome
What is the function of the mitochondria?
Generate majority of the ATP for the cell and the energy currency for the cell
what are ribosomes and the functions
site of protein synthesis
production of protein for the cell
How is it associated with the endoplasmic reticulum?
The rough endoplasmic reticulum has a rough section where many ribosomes, which is the location of protein production.
How is the mitochondria inherited?
Only from the mother
what is the endoplasmic reticulum and the function
Membrane organelle that extends throughout the cytoplasm
Storage site for calcium ions needed for cellular signaling
Produces, packages, and secretes many products of the cell (proteins + lipids)
what is the structure of the ER
Rough ER - because of its appearance
Connected flattened sacs having ribosomes
on its outer surface
Proteins modified by oligosaccharide
(carbohydrate)
Attachment of protein with oligosaccharide
= N linked glycosylation
Responsibilities
Site for synthesis of transmembrane
Making sure there is correct protein folding
(use of the N linked glycosylation)
Protein sorting
Smooth ER - because it has a smooth like appearance
Does not have any ribosomes
Responsibilities
Synthesis of lipids - phospholipids +
cholesterol
Production of steroid hormones
What is the Golgi apparatus and its function
Membrane bounded organelle made up of a series of flattened discs (cisternae)
Central sorting station for proteins and membranes along the secretory pathway
Synthesis site for most cellular carbohydrates
Protein modifications -
1) N linked oligosaccharides trimmed and
processed by addition of other sugars which
leads to complex oligosaccharides + high
mannose oligosaccharides
2) Some proteins have carbohydrates added to the hydroxyl group of serine/threonine = O linked glycosylation
Where are ribosomes found?
- cytoplasm
- mitochondria
- chloroplasts
what is the structure of the Golgi apparatus?
Flattened sacs (cisternae)
1) Cis face - closets to the ER
Receives vesicles containing ER synthesized proteins
2)Trans face - Furthest from the ER
Exit from the golgi apparatus
the golgi apparatus is a synthesis site for what metabolic structure
carbohydrates
what is the function of flippase?
generate asymmetry in the plasma membrane
what is the function of scramblase ?
generate symmetry in ER
