Chapter 6 - Structure and Function in Cells and Viruses Flashcards
Summarize the events in zygotene
- homologous chromosomes pair up (synapsis) in preparation for crossing-over (genetic recombination)
- the synaptonemal complex (RNA scaffold) appears between the pairing chromosomes and facilitates their union
1-letter abbreviation of isoleucine
I
Equation: isoelectric point (pI)
pI = [pKa1 + pKa2]/2
What are 3 major groups added to C1 of phospholipids?
- phosphoethanolamine
- phosphocholine
- serine
What is the beginning and end result of meiosis?
1 diploid cell makes 4 haploid cells
In the titration of protonated glycine by a strong base, how does its charge change over time and which groups are changing?
pH < pKa α-COOH: +1 (fully protonated)
First midpoint: pH = pKa α-COOH: +0.5
Equivalence point: pH = pI (physiologic pH): 0
Second midpoint: pH = pKa α-NH3: -0.5
pH > pKa α-NH3: -1 (fully deprotonated)
1-letter abbreviation of proline
P
What is simple diffusion?
spontaneous movement of solute molecules through a lipid bilayer, from high to low concentration (down the concentration gradient)
Cytosine structure

Lysine structure

In what direction do microfilaments grow (polymerize)? In what direction do they depolymerize?
They are polymerized fastest at the + end and depolymerize fastest at the - end.
What is the purpose of the rough endoplasmic reticulum?
The bound ribosomes synthesize membrane and secretory proteins that are then passed through into the lumen where post-translational modification begins. Modified proteins are shuttled to the Golgi apparatus.
What holds sister chromatids together?
centromere
What are anomers?
carbohydrates that differ diastereomerically (α/β) at the anomeric (C1) carbon
How do proteins get into the nucleus from the cytoplasm?
through nuclear pores that span the inner and outer membranes
What is nucleoplasm?
the mixture of chromatin and the aquous phase of the nucleus
What is the secondary structure of a polypeptide?
spatial arrangement of amino acids that are close to one another (β-pleated sheets and α-helices)
3-letter abbreviation of glycine
Gly
3-letter abbreviation of threonine
Thr
What is the general function of progesterone?
It prepares the uterine lining for implantation of an ovum and maintains it if implantation occurs.
What are bivalent chromosomes? Tetrads?
Those that have undergone synapsis in meiosis because there are four chromatids. The paired homologous chromosomes are also called tetrads.
In order for an organism to reproduce asexually, should it be diploid or haploid?
either
Alanine structure

Acrocentric chromatids

Summarize the events in Meiosis II: Telophase II
- nuclear membrane forms
- chromosomes decondense
- cleavage furrow of cytokinesis deepens
What are the two major types of bulk transport?
- endocytosis
- exocytosis
What are peripheral membrane proteins?
proteins weakly attached to the surface of the lipid bilayer
Summarize the events during anaphase
- centromeres aligned at the metaphase plate divide and the two sister chromatids can now be called daughter chromosomes, and move toward opposite poles
- microtubules exhibit depolymerization at the kinetochore
- cytokinesis begins (cleavage into two daughter cells)
- the cell is 4n
What is the difference between pyranose and furanose?
pyranose: 6-membered cyclic carbohydrate
furanose: 5-membered cyclic carbohydrate
What are the two structures of viruses?
- isometric
- helical
Describe prokaryotic DNA structure
double-stranded and circular
Bacteria sometimes have plasmids, which are also circular and double-stranded, but smaller

What are the convoluted foldings of mitochondria’s inner membrane called?
cristae
What is the sedimentation coefficient of eukaryotic ribosomes? What about the large and small subunits?
80S
Large subunit: 60S
Small subunit: 40S
What are mesosomes?
invaginations of bacterial cell membranes
What is the pKa of aspartate’s side chain?
3.9
1-letter abbreviation of methionine
M
Valine structure

What is chemotaxis?
attraction towards or repulsion away from certain chemicals (exhibited by bacteria)
Summarize the events during prophase
- centriole pairs begin to move apart and form microtubules that radiate from the centrosome or microtubule organizing center/MTOC (aster star)
- some microtubules attach at the kinetochore (near the centromere) of sister chromatids
- chromatin condensation is complete
- nucleolus disappears and nuclear membrane begins to break down
Fatty acid structure
carboxylic acids with a hydrocarbon side chain

Guanine structure

3-letter abbreviation of tryptophan
Trp
What are ampholytes?
amphoteric molecules that exist as zwitterions at physiological pH
What are nonhistones?
They are acidic proteins that bear a net negative charge and interact with DNA (ex: RNA polymerase)
3-letter abbreviation of valine
Val
1-letter abbreviation of serine
S
Summarize the events in diplotene
- crossing-over becomes visible at structures called chiasmata (single: chiasma)
What is the form of genetic information as a cell prepares for division?
chromosomes (highly condensed - visible)
In order for an organism to reproduce sexually, should it be diploid or haploid?
diploid
What is active transport? What are two types?
transportation of a solute from low to high concentration, requiring energy
- primary active transport
- secondary active transport
Which type of RNA helps define the site of protein synthesis?
ribosomal RNA (rRNA)
What is the general function of testosterone?
It aids in sperm maturation and development of secondary sex characteristics
What is the difference between an envoloped and non-enveloped virus?
An enveloped virus is surrounded by a lipid membrane that is attached to the nucleocapside by matrix proteins. A non-enveloped virus is not surrounded by a membrane (naked).
3-letter abbreivation of phenylalanine
Phe
Serine structure

What is primary active transport?
hydrolyzes ATP to ADP and Pi for energy to move molecules across their concentration gradients
What is the major reaction that takes place in the smooth endoplasmic reticulum of hepatocytes and what purpose does it serve?
hydroxylation, which aids in detoxifying drugs, making them more water soluble for elimination
What stabilizes β-pleated sheets in polypeptides?
hydrogen bonds between CO and NH groups of different polypeptide chains
What is a signal recognition particle?
It recognizes signal sequences in growing proteins, halts translation, and directs the ribosome to a signal sequence receptor on the rough ER. Translation restarts and the polypeptide is inserted into the ER lumen, where the signal sequence is removed by a signal peptidase and the polypeptide is modified.
What is the structure of microfilaments? What is their diameter? What are the main protein components?
- 7 nm
- G-actin monomers form F-actin polymer

3-letter abbreviation of arginine
Arg
What is the bond called between monosaccharides?
O-glycosidic linkage
Glutamine structure

Summarize the events in Meiosis II: Metaphase II
- chromosomes line up along the metaphase plate
How does a capsid differ from a nucleocapsid?
A capsid does not contain nucleic acid, so it is an empty shell. A nucleocapside contains nucleic acid.
Where is rRNA transcribed?
from specific genes of DNA within the nucleolus
How does salivary α-amylase break down starch? What about pancreatic α-amylase? What about intestinal enzymes?
Salivary α-amylase hydrolyzes many of the α(1–>4) linkages, breaking it down into oligosaccharides.
Pancreatic α-amylase hydrolyzes more linkages, breaking down the oligosaccharides into di- and trisaccharides.
Intestinal enzymes break it down into monosaccharides to be absorbed by the intestinal epithelial cells and passed into the blood.
What are some biochemical reactions that occur in the mitochondrial matrix?
- Krebs cycle
- β-oxidation of fatty acids
- ketone body metabolism
- gluconeogenesis
- urea cycle reactions
3-letter abbreviation of glutamine
Gln
What are the purine bases?
- adenine
- guanine
What is passive transport? What are the two types?
movement of a molecule from high to low concentration
- simple diffusion
- facilitated diffusion
What generally happens during the synthetic (S) phase?
All 46 strands of chromatin are replicated to make 92 sister chromatids. Daughter centrioles are synthesized.
Methionine structure

Describe the structure of gram (-) bacteria and how it affects their gram stain result.
They have a thin peptidoglycan layer between their plasma membrane and outer membrane. The outer layer contains lipopolysaccharides and porins.
They stain red/pink.

How are lysosomal enzymes made?
Glycoproteins that come from the Golgi are inactive precursors (proenzymes) that undergo proteolytic cleavage in an acidic environment (the lysosome) to form active enzymes.
Summarize the events in Meiosis I: Cytokinesis
- 2n –> n (reductive division)
What are the 4 phases of Meiosis I: Prophase I?
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis
What is the primary structure of a popypeptide?
the sequence of amino acids in a protein and location of disulfide bonds
Proline structure

1-letter abbreviation of leucine
L
What is the function phosphatase?
It hydrolyzes and removes phosphate groups from the substrate.
What is the form of genetic information in a nondividing (interphase) cell?
chromatin (not visible)
What is the purpose glycosidase?
It hydrolyzes and breaks down carbohydrates.
3-letter abbreviation of aspartate
Asp
1-letter abbreviation of tyrosine
Y
What is the major protein in mitochondria’s outer membrane and what is its function?
porin - a transmembrane protein that allows various molecules through
Which type of RNA allows for the synthesis of proteins?
messenger RNA (mRNA)
Whats is a cystine?
Two cysteine residues that are part of a disulfide bond are oxidized (lose their H’s).
Arginine structure

Equation: number of stereoisomers
2n
n = # of chiral centers
Summarize the events during metaphase
- chromosomes align at the equator of the cell (metaphase plate)
- nuclear membrane has completely disappeared
1-letter abbreviation of valine
V
Where are ribosomes found?
- cytoplasm
- rough ER
- mitochondrial matrix
What are the Tollens’ and Benedict’s reagents used for?
They test whether sugars are reducing sugars. They must contrain a hemiacetal or hemiketal group to give a positive test.
1-letter abbreviation of cysteine
C
Histidine structure

1-letter abbreviation of glutamine
Q
What is bacterial conjugation? What are the individuals involved called?
The transfer of DNA occurs through cell to cell contact between the donor (male/F+) and recipient (female/F-).
What is the function protease?
It hydrolyzes peptide bonds to break apart proteins.
Aspartate structure

1-letter abbreviation of aspartate
D
What group(s) do non-reducing sugars contain?
ketal/acetal
The nucleic acid polymer that has a sequence identical to a positive strand is positively or negatively stranded?
positively stranded
What is the bond that links the DNA/RNA backbone to nitrogenous bases?
N-glycosidic linkage (between pentose sugar and nitrogenous base)
What are the 3 major lipid components in eukaryotic membranes?
- cholesterol
- sphingolipids
- glycerophospholipids
Which amino acid is not referred to as and α-amino acid? What is it called?
proline (α-imino acid)
How do enveloped viruses acces a host cell?
- Receptor-mediated endocytosis
- direct fusion with the plasma membrane: must contact a specific receptor
Describe binary fission in bacteria
Replicated DNA becomes enclosed by a new plasma membrane and cell wall to eventually separate from the parent cell.
What is the general function of cortisol in the liver, skeletal muscle, and adipose tissue?
Liver: increase glycogen synthesis and gluconeogenesis
Skeletal muscle: decrease glucose uptake and protein synthesis, increase protein catabolism
Adipose tissue: increase lipid mobilization, decrease glucose uptake
1-letter abbreviation of threonine
T
What are carbohydrates called that have 3, 4, 5, 6, and 7 carbons?
- trioses
- tetroses
- pentoses
- hexoses
- heptoses
Asparagine structure

Which portions of DNA/RNA are polar/nonpolar?
polar: phosphate groups on backbone
nonpolar: nitrogenous bases
3-letter abbreviation of histidine
His
What composes a haploid (n) cell? Which cells are haploid?
22 autosomes
1 sex chromosome
Gametes are haploid.
What are the 3 main stages of the cell cycle and their components?
- interphase (G1, S, G2)
- mitosis (pro, meta, ana, telophases)
- cytokinesis
3-letter abbreviation of cysteine
Cys
What is the rolling circle mechanism of replication?
It is the mechanism used in bacterial conjugation to replicate the “fertility plasmid,” or “F factor.”
What is the region called between nucleosomes?
linker
What is the sedimentation coefficient of mitochondrial ribosomes?
55S
What is the role of starch?
food reserve in plants
Summarize the events in diakinesis
- nuclear envelope begins to break down, nucleoli disappear
- chiasmata move along the lengths of the chromatids until they reach the ends
- as the chromosomes begin to separate, they appear to be joined at their ends
How many carbons make up the simplest carbohydrates?
3
How do non-enveloped viruses access a host cell?
Receptor-mediated endocytosis:
The receptors are located near clathrin-coated pits that promote vesicle formation. A virus is endocytosed, the vesicle pH lowers, the clathrin coat depolymerized to form a smooth vesicle called an endosome. pH of the endosome continues to fall, disrupting the membrane, and releasing the virus.
In which meiosis does reductive division occur?
meiosis I (2n –> n)
1-letter abbreviation of tryptophan
W
In bacteria, where does replication begin on DNA?
replication origin
What is the tertiary structure of a polypeptide?
spatial arrangement of amino acids that are far from one another (all the α-helices and β-pleated sheets that make up a subunit)
Looking at a carbohydrate structure, what determines if it is D/L?
In a Fisher projection, look at the chiral carbon (also called reference carbon) farthest from the carbonyl carbon. If the hydroxyl group on that carbon is on the right, it is D. If it is on the left, it is L.
1-letter abbreviation of glycine
G
What generally happens during cytokinesis?
There is cytoplasmic division of a cell into two daughter cells.
Adenine structure

1-letter abbreviation of glutamate
E
How many amino acids make up an oligopeptide?
10+ amino acids
What keeps the lysosomal environment acidic?
an ATPase proton pump in its membrane pumps 2 hydrogens in for every hydrolyzed ATP
Phenylalanine structure

Equation: Henderson-Hasselbalch pH
pH = pKa + log [A-]/[HA]
3-letter abbreviation of aparagine
Asn
3-letter abbreviation of tyrosine
Tyr
What is secondary active transport?
ionic gradients that have been established by primary active transport systems provide the driving force that allows for cotransport of other molecules against their gradient
What is the function lipase?
It hydrolyzes and breaks down phospholipids.
Sucrose structure
α-D-glucopyranose and β-D fructofuranose (glucose + fructose)

What are the 3 families of amino acids?
- nonpolar R group
- polar R group
- charged R group
What is the role of glycogen? What is its structure?
It is the storage polysaccharide common to all animals, mainly in skeletal muscle and liver tissue.
It is a branched polymer of D-glucose with branch points every 8 to 12 residues.
3-letter abbreviation of alanine
Ala
What are glycoproteins?
carbohydrates that are attached to membrane proteins (exterior)
What composes a diploid (2n) cell? Which cells are diploid?
- 44 autosomes
- 2 sex chromosomes
Somatic cells are diploid.
Cysteine structure

3-letter abbreviation of isoleucine
Ile
What is the purpose of the Golgi apparatus? What are some example?
It chemically modifies proteins.
- Glycolsylation: addition of carbohydrates
- Sulfation: addition of inorganic sulfate
- Proteolysis: reducing the size of the protein
Tyrosine structure

Tryptophan structure

Uracil structure

Are D or L amino acids found in proteins?
L amino acids
What is the pKa of arginine’s side chain?
12.5
Summarize the events during telophase
- daughter chromosomes have reached each pole
- chromosomes begin to uncoil and extend
- microtubules being to disappear
- nuclear membrane forms around each of the two daughter nuclei
- nucleolus reappears
- cleavage furrow of cytokinesis deepens
- the cell is 4n
What are different shapes of bacteria?

What is the pKa of glutamate’s side chain?
4.2
1-letter abbreviation of asparagine
N
Summarize the events during Meiosis I: Metaphase I
- homologous chromosomes align on the metaphase plate
- centromeres appear to be distant, chromosomes seem to touch each other only at their ends
- microtubules are attached at the centromeres
- nuclear membrane has disappeared
Describe the difference between sister chromatids and homologs within a homologous pair.
Sister chromatids are the identical strands of each chromosome after replication. Homologs are individual members of a homologous pair (1 homolog from mom, 1 from dad)

What is the space within the endoplasmic reticulum?
lumen
Which type of RNA brings amino acids to the site of protein synthesis?
transfer RNA (tRNA)
What are the two forms of starch? Describe their structures.
α-amylose: a linear, unbranched polymer of D-glucose residues linked together in α(1–>4) linkages
amylopectin: a branched polymer of D-glucose residues linked together in primarily α(1–>4) linkages but at the branch points in α(1–>6) linkages (branch points every 24-30 residues)
What amino acid forms disulfide bonds?
cysteine
3-letter abbreviation of proline
Pro
What are the 5 major classes of steroids?
- androgens
- estrogens
- progesterone
- glucocorticoids
- mineralocorticoids
Summarize the events in leptotene
- the replicated chromosomes have begun to condense and become visible
What are the membranous sacs called in the Golfi?
cisternae
What are the two types of phospholipid movement within a bilayer and how frequent are they?
- lateral diffusion: between neighbors, happens frequently
- transverse diffusion: between layers, happens rarely
What are the pyrimidine bases?
- thymine
- cytosine
- uracil
1-letter abbreviation of phenylalanine
F
In hepatocytes, what is the final enzyme-catalyzed reaction that releases glucose from glygocen? What enzyme is used?
Glucose-6-phosphate + H2O —> Glucose + Pi
Enzyme that carries out reaction: glucose-6-phosphatase
The side chain of which amino acids is weakly ionized at neutral pH?
Histidine
At physiological pH, how are amino acids charged in their main structure? What is the term for this?
The α-amino group is positively charged, while the α-carboxyl group is negatively charged. They are zwitterionic.
Telocentric chromatids

3-letter abbreviation of methionine
Met
Is E. coli gram negative or positive?
gram negative
1-letter abbreviation of alanine
A
3-letter abbreviation of glutamate
Glu
3-letter abbreviation of serine
Ser
What is a symport?
integral membrane transporter that allows two different types of molecules (cotransport) to pass through in the same direction
What two functional groups must a carbohydrate have?
- aldehyde (aldose)/ketone (ketose)
- 2+ alcohol groups
Summarize the events in Meiosis I: Anaphase I
- microtubules pull homologous chromosomes apart toward each pole
- chromosomes still consist of sister chromatides (dyad)
- cytokinesis begins
What are inclusion bodies?
cytoplasmic structures within bacteria that store organice and inorganic molecules (like glycogen or phosphate)
What is the general function of aldosterone?
It increases the resabsorption of Na+, causing retention of Na+ in the ECF, thereby increasing ECF volume. This increases blood volume, pressure, and flow.
What is the structure of microtubules? What is their diameter? What are the main protein components?
- 25 nm
- α-tubulin + β-tubulin = dimer

Is viral mRNA positive or negative stranded?
positive stranded
Thymine structure

1-letter abbreviation of arginine
R
What happens to the hydrolysis products in a lysosome?
They diffuse out of the lysosome to be utilized in different organic processes.
What is the average pKa for the α-amino group on amino acids?
~9.4
What is the average pKa of α-carboxyl group on amino acids?
~2.2
What is an abbreviated drawn-out structure of a nucleotide?

What do bacteria use for movement? What is it composed of?
flagella, composed of the protein flagellin
2’ deoxy-D-ribose (DNA) and D-ribose structures

What is the order in which a protein passes through the Golgi?
cis ► medial ► trans
What is the basic molecular formula of carbohydrates?
(CH2O)n
Glycine structure

What is significant about the interphase between meiosis I and II?
It does not have an S phase.
What is the major type of active enzyme within a lysosome?
hydrolytic enzymes (acid hydrolases - they only function at acidic pH)
What is an antiport?
integral membrane transporter that allows two different solute molecules (cotransport) through in opposite directions
What eukaryote produces asexually?
yeast
How does the Benedict’s reagent react with an aldose/ketose?
The sugar is oxidized and the Cu2+ ion is reduced to give a brick-red precipitate.
What is the major enzyme in peroxisomes and what is its purpose?
Catalase degrades hydrogen peroxide that has accumulated from oxidation of fatty acids and amino acids.
2H2O2 —> 2H2O + O2
3-letter abbreviation of leucine
Leu
The nucleic acid template (complement) of a positive RNA strand is positively or negatively stranded?
negatively stranded
What are the 5 types of histones?
- H1
- H2A
- H2B
- H3
- H4
Metacentric chromatids

What are the 3 components of nucleotides?
- nitrogenous base
- pentose sugar
- phosphoric acid
What is the pKa of histidine’s side chain?
6.0
How does the Tollen’s reagent react with an aldose/ketose?
The sugar is oxidized and the Ag+ ion is reduced to silver metal, which precipitates as a silver mirror on the sides of the reaction vessel.
What is the directionality of a single strand of DNA?
5’ –> 3’
What is the quaternary structure of a polypeptide?
subunits that associate with one another
What is the structure of intermediate filaments? What is their diameter? What are the main protein components?
- 8-12 nm
- can be made of different proteins depending on the cell

What is a prokaryote? What are the two domains?
single-celled organism that lacks a nucleus, mitochondria, and any membrane-bound organelles
- Archaea
- Bacteria
What is a glycocalyx? What are two examples?
a polysaccharide layer that covers the surface of a bacterial cell
- capsule
- slime layer
What is the direction of amino acid synthesis?
amino terminal ► carboxyl terminal
What is the structural residue common to all sphingolipids? What is its structure?
Ceramide

What is a glycolipid?
a membrane lipid attached to a carbohydrate (usually on the exterior)
What are the 3 main components of a cell’s cytoskeleton?
- microtubules
- microfilaments
- intermediate filaments
Cholesterol structure

Glutamate structure

What four atoms make up the peptide bond?
amide: 0=C-N-H
1-letter abbreviation of histidine
H
Is the hydrolysis of a peptide favorable or unfavorable?
favorable
Peptide synthesis requires energy.
What is the purpose of nuclease?
It hydrolyzes and breaks down DNA.
What 3 molecules/organelles do mitochondria contain?
- DNA (mtDNA)
- ribosomes
- tRNA
What is the process called through which a virus introduces its genome into a host?
penetration
What are the 4 groups bonded to an amino acid’s α-carbon?
- basic amino group (NH2)
- acidic carboxyl group (COOH)
- hydrogen (H)
- specific side chain (R)
What is the sedimentation coefficient of prokaryotic ribosomes? What about the large and small subunits?
70S
- Large subunit: 50S
- Small subunit: 30S
How does the α anomer differ from the β anomer?
α anomer: OH group at anomeric carbon is on the opposite side of the ring from the CH2OH group attached to the reference carbon
β anomer: OH group at the anomeric carbon is on the same side of the ring from the CH2OH group attached to the reference carbon
From what region do microtubules grow? In what direction? What are 3 examples?
microtubule organizing centers (MTOC) add to the + end which extends toward the cell periphery
- centrosome
- kinetochores
- centrioles
What are integral membrane proteins?
proteins embedded in the lipid bilayer (either trans-membrane proteins or exposed at only the interior/exterior)
What are the core histones involved in nucleosomes?
- H2A
- H2B
- H3
- H4
What is Tay-Sachs disease?
a recessive disorder in which there is an absence of the lysosomal enzyme hexoaminidase A , allowing accumulation of a particular glycolipid within the lysosome
Summarize the events in pachytene
- chromosomes continue to condense and become more distinct
- genetic recombination occurs via crossing-over
What is a uniport?
integral membrane transporter than only allows one type of solute through in one direction
Describe the structure of gram (+) bacteria and how it affects their gram stain result.
They have a thick peptidoglycan layer outside their plasma membrane. They also have techoic acids that extend to the surface of the cell.
They stain purple.

What is sphingomyelin’s structure? Where is it found?
sphingolipids with phosphoethanolamine or phosphocholine attached to the C1 of the ceramide
They are abundant in myelin sheaths.
What holds nitrogenous bases together?
A=T: 2 hydrogen bonds
C≡G: 3 hydrogen bonds
What generally happens during the second growth phase (G2)?
Chromatin begins to condense, and protein synthesis is quite active as the cell prepares for mitosis.
Sucrose structure
β-D-galactopyranose and β-D-glucopyranose
(galactose + glucose)

What is facilitated diffusion?
movement down a concentration gradient with the help of integral membrane proteins
What is bacterial transformation?
uptake of DNA from the surrounding medium
Define permease
protein transporters that allow for movement of a solute across a membrane
Triacylglycerol structure
glycerol + esterified fatty acids

What is the pKa of lysine’s side chain?
10.8
In what organelle are steroids synthesized?
mitochondria
Threonine structure

What are histones made of?
They are basic proteins consisting of a high percentage of lysine and arginine residues, with positively charged amino groups at physiologic pH, allowing an electrostatic relationship with the negatively charged DNA.
What is the host range of a virus?
viral specificity for a host cell, dependent upon the interaction of a virus with the host cell’s surface proteins, glycoproteins, and glycolipids
What is pinocytosis?
endocytosis of extracellular fluid (ECF)
What is a nucleosome?
a specific length of DNA coiled around histones
What is phagocytosis?
endocytosis of particulate matter
Which cells do not contain mitochondria?
erythrocytes
Within what range is a weak acid in its buffering range?
within 1 pH unit of its pKa
3-letter abbreviation of lysine
Lys
Summarize the events in Meiosis II: Prophase II
- chromosomes begin to condense
- microtubules attach to the kinetochores of each chromosome
What are the 3 types of bacterial DNA transfer?
- conjugation
- transformation
- transduction
What are the building blocks of a virus’s protein coat?
capsomers
What takes place of the nucleus in prokaryotes?
nucleoid
Leucine structure

Isoleucine structure

What is the bond called that links nucleotide units?
phosphodiester bond (between pentose sugar and phosphate group)
Summarize the events in Meiosis II: Anaphase II
- centromeres divide, and chromatids of each of the 23 chromosomes are pulled to opposite poles
- cytokinesis begins
- cell is 2n
What are glycerophospholipids? What is their structure?
They are the main component of all biological membrane (phospholipids)
Glycerol + 2 fatty acids (C1, C2) + phosphate (C3) which bears a negative charge at physiologic pH

What generally happens during the first growth phase (G1)?
RNA and proteins are synthesized, the centriole pair separates, the cell and its nucleus begin to increase in volume.
The side chains of which amino acids are highly ionized at neutral pH?
- Aspartate
- Glutamate
- Lysine
- Arginine
What is the general function of estradiol?
It regulates the ovarian cycle, controls certain metabolic processes, and develops secondary sex characteristics.
What stabilizes α-helices in a polypeptides?
hydrogen bonding between CO and NH groups that are 4 residues apart
What is bacterial transduction?
Viruses infect a host cell with their DNA. When they leave, they remove their DNA and sometimes remove some of the host’s DNA with it. In this way, they can transfer bacterial DNA.
What is the reference compound for the L and D designation of carbohydrates?
Glyceraldehyde
Define the isoelectric point (pI) of an amino acid
the pH at which an amino acid carries no net electric charge
How does amino acid separation work by electrophoresis?
If two amino acids are placed in an electric field, any whose pH > pI will migrate toward the anode (positive electrode), while any whose pH < pI will migrate toward the cathode (negative electrode).
1-letter abbreviation of lysine
K
Summarize the events during Meiosis I: Telophase I
- the migrating chromosomes (dyads) are at each pole
- nuclear membrane reforms
If a cell is destined to never divide, it will remain arrested in which phase?
first growth phase (G1)
What are sphingolipids derived from?
lipids not based on a glycerol backbone. Instead they are derivatives of amino alcohols