Flashcards in Exam 2 Review Deck (140):
What is a gene?
a locus (region) of DNA that encodes a functional RNA or protein product, it is also the molecular unit for heredity
What is the molecular unit for heredity?
a gene (the smallest unit of measurement)
What is a polypeptide?
a chain of amino acids, proteins are made up of one or more polypeptide molecules
Amino acids are linked _____ in _____ bonds in order to form a polypeptide.
What are the subunits of proteins?
What are the 5 main functions of nucleic acids?
heredity (store and transport information), cell control, energy storage, electron carriers, and signaling (i.e. DNA and RNA)
What is the central dogma of molecular biology?
DNA can be copied into DNA (replication). DNA codes for RNA, which codes for proteins. DNA is responsible for heredity (passing of traits onto offspring). It contains the instructions for building RNA and proteins, which make up the structure of the body and carry out most of its functions.
What is the coding of DNA to RNA called?
What is the coding of RNA to a protein called?
What is the process of DNA creating more DNA?
What is a macromolecule?
a series of small subunits covalently bonded to form a larger molecule
What is a monomer?
one subunit (relatively small molecule)
What is a dimer?
What is a trimer?
What is a tetramer?
What are the subunits of lipids?
fatty acids and glycerol
What are the subunits of carbohydrates?
What are the subunits of nucleic acids?
What are isomers? Give an example.
molecules that have the same chemical formula, but a different arrangement of atoms in space (fructose and glucose)
Plants store energy as _____ while animals store energy as _____.
What is a disaccharide?
a sugar composed of two monosaccharides
What are the three types of lipids?
triglycerides, phospholipids, and steroids
What is polymerization?
a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks
Subunits of a macromolecule are joined together in _____ bonds.
What type of reaction is responsible for the polymerization of the four main types of subunits/molecules?
a condensation reaction (a reaction accompanied with the formation of a water molecule, water is lost), also known as a "dehydration reaction"
What type of covalent bond do amino acids form?
What type of covalent bond do fatty acids and glycerol form?
What type of covalent bond do monosaccharides form?
What type of covalent bond do nucleotides form?
Are lipids hydrophobic or hydrophilic?
hydrophobic (not soluble in water)
What are triglycerides responsible for?
What are phospholipids responsible for?
What are steroids responsible for?
signaling (hormones) and membranes
What are triglycerides responsible for?
What are the components of a triglyceride?
one glycerol and three fatty acids
Within a triglyceride, each carbon atom will form exactly _____ bonds with other atoms.
What is a glycerol molecule?
three carbons and three hydroxyl (OH-) groups
What is a fatty acid?
chain of carbons (CH2) with carboxyl (COOH-) at one end, and CH3 on the other
What is a carboxyl group?
How many carbons exist between the carboxyl and CH3 in a fatty acid?
Fatty acids are amphipathic, which means _____.
the two ends of the molecule differ in chemical properties
The hydrophilic part of a fatty acid consists of the _____ group, which means that this part of the molecule is _____.
carboxyl, polar (because water is polar, too)
The hydrophobic part of a fatty acid consists of a _____ chain and a _____ molecule, which means that this part of the molecule is _____.
carbon/hydrogen chain, CH3, nonpolar (because water is polar)
What does "saturated" mean when it comes to fatty acids?
hydrogen occupies all available bond space
What does "unsaturated" mean when it comes to fatty acids?
hydrogen does not occupy all available bond space
What forms if two adjacent carbons are missing hydrogen atoms within a fatty acid?
a double bond
Saturated fats are "regular," so they form _____.
Saturated fats have _____ melting points.
Unsaturated fats have _____ melting points.
What is a fatty acid "tail"?
string of carbons
Saturated fates have _____ bonded carbons because all of the bond space is occupied with hydrogen.
Unsaturated fats have _____ or _____ bonded carbons because not all of the bond space is occupied with hydrogen.
Unsaturated fatty acids are usually in _____ form and have _____ tails.
Saturated fatty acids are usually in _____ form and have _____ tails.
Amphipathic lipids form _____ in water.
What is a micelle?
a lipid molecule that arranges itself in a spherical form in an aqueous solution
An amphipathic lipid has a _____ head and a _____ tail.
What is the function of a phospholipid?
What happens when two hydroxyl groups meet of fatty acids?
The fatty acids bond, sharing the oxygen of one OH-, while the other becomes part of the water molecule that is lost.
What does a phospholipid consist of?
two fatty acid tails attached to the glycerol molecule, one phosphate (PO43-), and an R group
What does the "R" in "R group" stand for?
residue (as in an undefined molecular group, such as H, OH, CH3, etc.)
A phospholipid is has a _____ head and two _____ tails, which means that it is amphipathic.
Micelles _____ when they come into contact.
The fusing of micelles is a _____ process.
What is solubility of lipids in water determined by?
length of chains (tails), and saturation
Membranes in cells consist of _____ layers of phospholipids. This is called a singular _____ membrane. Understand this structure.
two, bilayer (hydrophilic heads face outward and inward toward the cell, and the hydrophobic tails face each other)
A double membrane consists of how many bilayers and how many phospholipid layers?
What is the "fluid mosaic model"?
the idea that membranes are fluid (with other components), to form a patchwork pattern of phospholipids with IMP's and PMP's scattered about
What is an integral membrane protein (IMP)?
a protein that spans the width of the membrane
What is a peripheral membrane protein (PMP)?
a protein that is embedded in the membrane but not all the way through
Name three functions of proteins.
channels (IMP), enzymes, and carriers
Membranes are fluid, so if they are pressed together, they will _____.
Name four things that will enhance the fluidity of a membrane.
warm temperatures, cholesterol, shorter fatty acid tails on the phospholipids, less saturation
Organic compounds always contain _____.
Micelles are specifically _____ molecules.
What are two of the functions of steroids?
increased membrane fluidity, hormones
What is the structure of a steroid?
ring structure, one carbon at every point of ring, other molecules also attached
What, specifically, is a hormone?
a steroid- signaling molecule that is derived from cholesterol
Is "equilibrium" synonymous to "equal distribution"?
How can you increase the rate of diffusion?
by adding energy
What does "turgid" mean?
Active transport requires _____.
energy (in the form of ATP)
What are the two major functions of macromolecules?
cytoskeleton (structural) and enzymes (functional)
What are the main three functions of enzymes?
catalysts, controls whether a reaction occurs, controls reaction speed
What are four important types of carbohydrates?
sugar, starch, glycogen, and cellulose
What are all membranes made out of?
lipids and proteins
More saturation results in _____ fluidity.
What are the two types of facilitated diffusion?
channel-mediated and carrier-mediated
What is simple diffusion?
random molecular movement so that eventually molecules become evenly distributed
What effect does energy have on simple diffusion?
it speeds up the process
Dialysis tubing is an example of a _____ or _____ permeable membrane.
What does tonicity mean?
What is plasmolysis?
the process of a cell using water in a hypertonic solution
The _____ is responsible for carrier-mediated diffusion.
peripheral membrane protein (PMP)
What is endocytosis? What effect does this have on the cell membrane?
movement into a cell, decreases the amount of cell membrane (vesicle used inside cell)
What is exocytosis? What effect does this have on the cell membrane?
movement out of a cell, increases the amount of cell membrane (vesicle that was used inside of cell becomes part of the membrane)
A _____ describes repeatedly dividing a cell.
What is the clockwise "order" of components of the cell cycle clock, starting in the upper righthand corner?
G1 - S - G2 - M
What happens in G1?
this is "gap one," when the cell grows
What happens in S?
synthesis (DNA synthesis/replication)
What happens in G2?
this is "gap two," when the cell prepares for division
How can you describe, specifically, S (synthesis)?
single chromosome becomes double (they are both "one" chromosome, but with twice as much "stuff" after replication) -- 00 is one chromosome with one chromatid (monosome), 88 is one chromosome with 2 chromatids (disome)
What is the M phase on the cell cycle clock?
What is meiosis?
sexual reproduction, one nucleus becomes four, introduces variability (nuclei are not identical)
What is mitosis?
vegetative, somatic, asexual
responsible for growth, cell replacement, wound repair, hair and nail growth
results in two nuclei that are clones
What is cytokinesis?
the division of cell cytoplasm (may or may not occur after both meiosis and mitosis), the nuclei coexist in the cytoplasm until this occurs
What is G0?
Where cells go to no longer divide (outside of G1). They can pretty much enter and leave this state as they please.
The cell will divide if _____.
it passes the point of no return (a point on G2)
What is a "checkpoint" of cell division?
self-assessments to make sure the cell should divide (not going through the G2 checkpoint could result in cancer, where cell division is out of control)
What is a chromosome defined as?
one DNA molecule with its associated histone proteins (proteins that provide a "framework" for DNA to wrap around like a scarf)
How many types of histones are there?
What is an "interphase chromosome"?
one that is not wrapped or coiled tightly, it is invisible and called "chromatin," essentially an invisible blob
What happens to chromosomes during the "M phase"?
The chromosomes condense, making it easier for them to separate (rather than a glob, it's little 88 things)
What are the four main stages of mitosis, in order?
Describe what happens in the prophase of mitosis.
the centriole divides and migrates to the poles, the chromosomes condense, the nuclear envelope "disappears," and the spindle forms (microtubules (MTOC) and centrioles)
Describe what happens in the metaphase of mitosis.
chromosomes align at the equatorial plane and attach to the spindle
Describe what happens in the anaphase of mitosis.
the two halves of the chromosome separate, pulled by the spindle to opposite poles of the cell
Describe what happens in the telophase of mitosis.
the chromosomes have reached the poles of the cells, the nuclear envelope reforms, chromosomes decondense, the product is one cell with two nuclei (time for cytokinesis!)
How does cytokinesis work in bacteria?
no "M" phase because there is no nucleus, division in a process called "fission"
How does cytokinesis work in animal cells?
Furrowing- microtubules reorganize and pinch the cell in two
How does cytokinesis work in plants?
"phragmoplast" found in plants is used
What is the general structure of DNA?
DNA is a polymer of nucleotides, large subunits linked by covalent bonds (that are formed in the condensation/dehydration reaction)
What is the structure of a nucleotide?
sugar, phosphate, base
What does the sugar look like within a nucleotide?
5 carbons, ribose, deoxyribose (if it lost an oxygen)
Where is the phosphate molecule located within a nucleotide?
at carbon #5 (one of three phosphates is attached here)
What are the five possible bases of a nucleotide?
adenine, thymine, cytosine, guanisine, uracil (RNA only)
Where does the base attach within a nucleotide?
carbon number one
How are the carbons within a nucleotide ordered?
1-5 starting at the right upper corner and going clockwise
What is ATP as far as nucleotides go?
a nucleotide triphosphate
Which bases are pyrimidines?
cytosine, thymine, uracil
Which bases are purines?
How does the polymerization of nucleotides work?
polymerization=chain building, from the 5' (front/phosphate) to 3' (tail) end
What is the result of the polymerization of nucleotides?
a DNA (sugar-phosphate) backbone
DNA is _____ stranded.
What type of bond holds the two DNA strands together?
What stage of the cell cycle does DNA coil?
How many hydrogen bonds does the base pair A=T have?
How many hydrogen bonds does the base pair C=G have?
What does "denature" mean?