Bio/Biochem Flashcards
How does ABO blood typing work?
Alleles are alternative forms of the same gene. In human blood types, there is one locus (location) that codes for blood group, and there are three possible common alleles: IA, IB, and i.
All humans and many other primates can be typed for the ABO blood group. There are four principal types: A, B, AB, and O. There are two antigens and two antibodies that are mostly responsible for the ABO types. The specific combination of these four components determines an individual’s type in most cases.
What is Autosomal Dominance?
A pattern of inheritance in which an affected individual has one copy of a mutant gene and one normal gene on a pair of autosomal chromosomes. (In contrast, autosomal recessive diseases require that the individual have two copies of the mutant gene.)
What is Penetrance?
refers to the proportion of people with a particular genetic variant (or gene mutation) who exhibit signs and symptoms of a genetic disorder.
If some people with the variant do not develop features of the disorder, the condition is said to have reduced (or incomplete) penetrance.
What is Expressivity?
the degree to which a phenotype is expressed by individuals having a particular genotype.
What is the Law of Independent Assortment?
states that the alleles of two (or more) different genes get sorted into gametes independently of one another.
In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.
What does a 50% Recombinant Frequency mean?
The likelihood of independent assortment for genes on different chromosomes is 50%. If, however, genes on the same chromosome are situated sufficiently far apart, they could also approach a recombination frequency of 50%.
What is Codominance?
Codominance is the idea that two dominant phenotypes can be expressed simultaneously without a blend. For example, two dominant colored parents may produce a striped child. The ability to produce multiple proteins from the same gene is an example of codominance, because multiple phenotypes are co-existing simultaneously.
What is Autosomal Recessivity?
Autosomal Recessivity is one of several ways that a trait, disorder, or disease can be passed down through families.
An Autosomal Recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop.
What is Gene Linkage?
Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction.
Hint! Keep an eye out for phenotypic ratios being messed up. This may be an indicator of gene linkage.
Question wrong explanation:
“Because the phenotypic ratio of certain traits violated what was expected, the genes are likely linked and are therefore close to one another on a chromosome. Linked genes are found close together on the same chromosome and have a higher likelihood of being inherited together.”
What is genotypic ratio of a “carrier” of an autosomal recessive disorder if both parents are carriers?
Disease penetrance * genotypic ratio of a carrier based on Punnett Square
What is the Law of Segregation?
Law of Segregation states that a diploid organism passes a randomly selected allele for a trait to its offspring, such that the offspring receives one allele from each parent.
Nondisjunction during meiosis
What happens to accuracy and probability of a double crossover event as recombination frequency increases and becomes > 50%?
The greater the likelihood of a double crossover event, the farther apart two genes are. The farther apart two genes are (>50%), the poorer double crossover events are as an estimation of gene distance.
Because crossovers occur randomly along the lengths of chromosomes. Within any region, the occurrence of 2 events is less likely than the occurrence of 1 event.
-If the probability of one event is 1/x, then the probability of 2 events occurring at the same time is 1/x^2
What is Recombinant Frequency?
(# of recombinants)/(# of total offspring) = recombination frequency
Each percent of a particular recombination frequency is measured as one centimorgan of distance along a chromosome.
What does Wild Type mean?
The definition of “wild type” refers to the traits an organism typically exhibits when found in nature. These may be dominant traits but not always.
If there is initially an even population of blue butterflies with small wings versus a black butterflies with large wings but something happens and only black butterflies with large wings constitute the butterfly population, what can be said about the butterfly trait of “blue”?
Selection pressures can decrease a trait’s frequency even if that trait is not deleterious and the pressure is not directly acting against the trait.
If you have two individuals w/ three traits, what are the unique possible genetic combinations?
Know if you have 2 individuals w/ 3 traits then the formula for possible unique outcomes is (allele number)(gene number) = possible combinations.
Can mutations found in non-germ cell tumors be hereditary?
Know that only mutations in germ cells are hereditary. Put another way, somatic mutations cannot be passed to offspring.
What is the Transmissibility of X-linked dominant genes?
Y-linked?
X-linked dominant genes are 50% transmittable to sons by mothers. Y-linked dominant genes from fathers are 100% to sons. (Rare)
How does ABO heritability work? Explain A, B, and O.
A and B are dominant and O is recessive. (Know Punnett Square for ABO blood typing and possibly what the antigens/antibodies terminology is referring to)
How do you tell phenotypically/genotypically if a population is not assorting independently?
Phenotypic and genotypic ratios in terms of whole numbers and % values are going to be roughly matching. Phenotype differs from genetic ratio if genes are NOT assorting independently. Factoid.
What are the traits (3) of Genetic Drift?
1) It causes random changes in allele frequencies.
2) It can lead to loss of genetic diversity.
3) It has a greater effect in small populations.
Elaborated:
1) As genetic drift is not a selective force, it causes populations to evolve at random based on which alleles are reproduced more often over many generations. Genetic drift occurs in the bottleneck effect and in the founder effect.
2) Genetic drift can cause allele fixation, which occurs when one or more alleles of a gene are randomly eliminated from a population over time, resulting in only a single possible genotype at that locus.
3) Genetic variation is more easily lost in small populations, since rare alleles may never be passed along to the next generation. Because genetic drift causes random fluctuations in allele frequencies, it has a more profound affect in smaller populations.
Is there a causal relationship between Fitness and Natural Selection?
There is not a causative relationship between these terms.
MEANING
Fitness does not result in natural selection.
NOR DOES
Natural selection result in fitness.
Natural selection refers to differential survival and reproduction of individuals with different traits. The fitness of a trait tells us how likely it is to remain within a population over time
Fitness is a quantitative measure of natural selection, so it cannot be said to result in natural selection.
What are the reasons (2) why the biological species concept is problematic?
It does not apply to organisms that reproduce asexually
AND
It does not account for hybrid organisms.
What are some things (4) you would expect to find from a sample of a plasma membrane?
Cholesterol, Enzymes, Sphingomyelin and Glyceroglycolipids
What is Sphingomyelin?
Sphingomyelin is a glycolipid with a sphingosine backbone in place of the glycerol that is found in phospholipids and glycoglycerolipids. Sphingomyelin clusters with cholesterol to make lipid rafts, which modulate membrane fluidity and serve as organized clusters for various signaling processes.
What are Glyceroglycolipids?
Glyceroglycolipids are a glycolipid type, which is a major class of membrane lipids. Glyceroglycolipids are similar to phospholipids in that they have a glycerol backbone and two fatty acid tails. However, glyceroglycolipids replace their phosphate group with a carbohydrate group.
What are Peripheral Proteins?
Peripheral proteins form temporary bonds with the cell membrane, allowing them to detach and reattach at specific times, with specific signals. This allows cells to coordinate and communicate using networks of proteins and reactions.
Peripheral proteins are found within the cytoplasm and are temporarily attached to integral proteins or are associated with lipid bilayer’s peripheral regions. They tend to interact only briefly with the membrane before resuming their function in the cytoplasm. This category includes some enzymes and hormones.
One example is aquaporin, the water transporter. The peripheral proteins can attach to the membrane surface by ionic interactions with an integral membrane protein (or another peripheral membrane protein) or by interaction with the polar head groups of the phospholipids.
What is cholesterol’s role in membrane fluidity?
Cholesterol helps prevent phospholipids from extreme stacking or motion:
In cold temperatures, the hydrophobic tails of lipids will bunch together. Cholesterol with its four-ring structure that gives it a very different, bulky, rigid, and short shape in comparison to the long, skinny, flexible fatty acid tails physically obstructs the tight packing of lipid tails. Therefore, cholesterol promotes membrane fluidity at low temperatures.
At high temperatures, the phospholipids move energetically increasing membrane fluidity. Cholesterol physically obstructs phospholipids from extreme motion with its large, bulky structure. In this way, cholesterol ensures membrane fluidity does not detrimentally increase.
Can glyceroglycolipids form lipid rafts?
No, while both glyceroglycolipids and sphingolipids have hydrophobic tails, glyceroglycolipids do not form lipid rafts with cholesterol.
ONLY Special sphingolipid sphingomyelin clusters with cholesterol molecules to form structures known as “lipid rafts”, which modulate membrane fluidity and various signaling processes.
Can sphingolipids modified w/ a carbohydrate group be involved in cell signaling?
Yes, they are called Cerebrosides and Gangliosides.
And again, you have your standard cell communication lipids, Glyceroglycolipids, which are amphipathic, modified with a carbohydrate group, and that they’re broadly involved in cell signaling and adhesion processes, in addition to being important plasma membrane components.
What is a Glycoprotein?
Glycoproteins are proteins attached to an oligosaccharide group. Many important proteins throughout the body are actually glycoproteins or are glycosylated. Examples include the major histocompatibility complex and the antigens of the ABO blood type system. Not surprisingly, membrane glycoproteins are often involved in cell recognition and communication processes.
What are Lipid-Anchored Proteins?
Lipid-anchored proteins are covalently bound to single or multiple lipid molecules. This arrangement anchors the protein within the membrane, without having it actually touch the membrane itself. G proteins are intracellular membrane-bound structures that help coordinate the signaling cascade initiated by the G protein-coupled receptors.
What direction do Flippases and Floppases move lipid leaflets?
Floppases move phospholipids from the inner leaflet to the outer leaflet.
Flippases move phospholipids from the outer leaflet to the inner leaflet.
Can you increase temperature to cause increased diffusion rates of the plasma membrane?
Yes, as temperature increases, membrane fluidity increases. Membrane fluidity makes some space for molecules to diffuse through the membrane, increasing diffusion. Increasing temperature is the simplest approach to help improve diffusion rates because an increase in temperature will cause the membrane to become more fluid.
What does “hydrophobic interactions” of phospholipids refer to?
Rigidity of phospholipids at low temperature is based on hydrophobic tails bunching up together. Cholesterol increases membrane fluidity by preventing the linear fatty acid tails from packing tightly.
What is diffusion?
Diffusion is the process of molecules moving from an area of higher concentration to an area of lower concentration until equilibrium is reached so the concentration of solute throughout the solution is even.
How many osmoles does 1M MgCl3 dissociate into?
The osmosis equation is: π = iMRT
4 Osmoles, 1M Mg and 3 - 1MCl ions.
What is Osmolarity?
Osmolarity is like molarity, except that it takes into account ALL solute particles. Magnesium chloride will dissociate to form three ions - two chloride anions and one magnesium cation in solution. The osmolarity will be 2M MgCl2 x 3 particles/ MgCl2 molecule = 6 osmoles.
Does Facilitated Diffusion operate under the same mechanisms as Osmosis?
Facilitated diffusion is passive transport, as no ATP is used either directly or indirectly. This describes secondary active transport because ATP is consumed and the energy is stored as an ion concentration gradient for later use. Both osmosis and facilitated diffusion are driven by differing concentration gradients across a membrane.
What are the types of Active Transport?
Primary and Secondary
An example of active transport is the sodium-potassium pump.
Is an Antiporter a type of Active Transport?
Yes.
Secondary active transport is a combination of active and passive transport. The active transport generates a concentration gradient that powers the passive transport of something else. Antiporters move two solute types in opposite directions. One solute moves with its concentration gradient and the other moves against its own concentration gradient.
What are the properties (3) of an Endosome?
Properties of endosomes include:
- Endosomes are bound to the plasma membrane on the intracellular side.
- Endosomes identify receptors that should be sent back to the plasma membrane.
- Endosomes are organelles.
What are the three major methods of Endocytosis?
Phagocytosis is the ingestion of solid particles.
Pinocytosis is the ingestion of large quantities of liquids or solutes.
Receptor-mediated endocytosis is the ingestion of specific molecules, like iron, from the extracellular environment.
What does Osmosis deal with?
Osmosis deals with the movement of solvent molecules, not solute molecules. Water is a solvent that can diffuse across the plasma membrane through aquaporins (channel proteins specific to water transport) via facilitated diffusion.
Is ATP the only necessary source for Primary Active Transport?
Primary active transport requires energy, which can be in the form of ATP hydrolysis, but can also be from other sources such as redox reaction or light. Therefore, ATP consumption is not a requirement of primary active transport.
Does Primary Active Transport require a medium to transport molecules?
Yes. In Primary Active Transport a protein channel is needed to carry out this function.
What are Proton Pumps in the ETC powered by?
Proton pumps of the electron transport chain are powered by redox reactions, not ATP hydrolysis.
How does Secondary Active Transport work?
Secondary active transport is powered by concentration gradients that have been established by primary active transport.
What are examples of Secondary Active Transport?
Both symporters and antiporters are examples of secondary active transport, but only antiporters will always promote movement of molecules into the cell.
Symporters and antiporters use secondary active transport, as they do not directly consume energy. Both allow molecules to move down their concentration gradients to harness their energy to power an unfavorable transport task. More specifically, the spontaneous transport of one substance (usually an ion) down its electrochemical or concentration gradient is coupled to the non-spontaneous transport of another substance against its gradient. Both symporters and antiporters can move molecules into the cell.
What molecules does receptor-mediated endocytosis ingest?
Specific molecules, like low-density lipoproteins, are taken in through receptor-mediated endocytosis.
What is a Lysosome?
Lysosomes are responsible for degrading ingested substances via endocytosis in order for the cell to repurpose the basic building blocks of the ingested material for other uses.
What are Late Endosomes?
Late endosomes are responsible for the identification and transport of substances that have been ingested via endocytosis and need to be degraded by lysosomes. However, late endosomes are not responsible for the actual degradation themselves.
What is the difference between Facilitated Diffusion and Passive Diffusion?
The primary difference between facilitated diffusion and passive diffusion is the presence of a protein channel with facilitated diffusion.
Facilitated diffusion does not require any energy (either directly or indirectly) and nor does passive diffusion. Both rely on diffusion, which is the tendency of molecules to spread out and their concentrations throughout a solution to equilibrate. Facilitated diffusion is passive diffusion through a protein channel to helps very polar molecules cross the hydrophobic plasma membrane core.
What is a Prokarotic genome made of?
The prokaryotic genome is a small, circular, double-stranded DNA genome.
Do Prokaryotes have an Electron Transport Chain?
In prokaryotes, the ETC is located in the cell membrane.
What does Ionizing Radiation do to Viruses/Prions?
Ionizing radiation damages nucleic acids and leads to mutations. As viruses depend on intact nucleic acids for their genetic information, it is unlikely that CJD has a viral cause. Peptide bonds are less affected by ionizing radiation. One hallmark of prion proteins is their thermodynamic stability.
Which labeled tubes depict organisms that exclusively exhibit anaerobic respiration?
Tubes 2 and 4.
What do all the oxygen requirements for microorganisms look like?
The bacteria are obligate (strict) aerobes that cannot grow without an abundant supply of oxygen. Tube B looks like the opposite of tube A. Bacteria grow at the bottom of tube B. Those are obligate anaerobes, which are killed by oxygen. Tube C shows heavy growth at the top of the tube and growth throughout the tube, a typical result with facultative anaerobes. Facultative anaerobes are organisms that thrive in the presence of oxygen but also grow in its absence by relying on fermentation or anaerobic respiration, if there is a suitable electron acceptor other than oxygen and the organism is able to perform anaerobic respiration. The aerotolerant anaerobes in tube D are indifferent to the presence of oxygen. They do not use oxygen because they usually have a fermentative metabolism, but they are not harmed by the presence of oxygen as obligate anaerobes are. Tube E on the right shows a “Goldilocks” culture. The oxygen level has to be just right for growth, not too much and not too little. These microaerophiles are bacteria that require a minimum level of oxygen for growth, about 1%–10%, well below the 21% found in the atmosphere.
What is the Lytic Cycle?
The lytic cycle, which is also referred to as the “reproductive cycle” of the bacteriophage, is a six-stage cycle. The six stages are: attachment, penetration, transcription, biosynthesis, maturation, and lysis.
What is the Lysogenic Cycle?
The lysogenic cycle is a method by which a virus can replicate its DNA using a host cell. Typically, viruses can undergo two types of DNA replication: the lysogenic cycle or the lytic cycle. In the lysogenic cycle, the DNA is only replicated, not translated into proteins.
What is the process of a retrovirus DNA infection?
A retrovirus consists of RNA that is later reverse-transcribed into DNA and then integrated into the host genome. From there, the host cell machinery transcribes that DNA into mRNA. Thus, the mRNA of the transcribed viral DNA should be identical to the actual viral genome.
What are the characteristics that define the sites recognized by restriction enzymes?
4-8 base pairs, DNA, Palindromic with respect to the complement (i.e. TTGCAA)
4-8 base pairs - Restriction sites, palindromic sites are restriction enzymes cleave, are typically around four to eight base pairs long.
DNA - Restriction sites, palindromic sites are restriction enzymes cleave, are found in double-stranded DNA.
Palindromic - Restriction sites are palindromic with respect to the complement. These sequences are characterized by inverted repeats in which the 5’ to 3’ sequence on one strand is identical to the 5’ to 3’ sequence on the complementary strand.
How do plasmids replicate?
Plasmids replicate independently of their bacterial chromosome. Therefore, the gene within the plasmid can be amplified to a larger degree than would otherwise be possible.
What are the steps for generating recombinant DNA?
Steps for generating recombinant DNA are as follows:
- Synthesize a gene sequence (or “insert”) with the proper restriction sites.
- Digest the insert and whatever relevant vector components (such as a plasmid) with corresponding restriction enzymes, which cleave at the designed restriction sites.
- Ligate the vector and the insert together with DNA ligase.
- Insert plasmid into the bacteria to be replicated.
- Finally, select for and isolate bacteria containing the plasmid of interest by some means (usually a reporter gene or by treatment with antibiotics).
What is the purpose for including an antibiotic resistance gene in a vector designed to generate recombinant DNA?
Engineering plasmids with antibiotic resistance genes enable them to be separated on the basis of antibiotic resistance. When we treat a plate of bacteria with an antibiotic, only those containing the antibiotic resistance gene will survive. Those that contain this antibiotic resistance gene will also contain the gene of interest.
What RNA polymerase initiates transcription in eukaryotes?
In eukaryotes, RNA polymerase II synthesizes heteronuclear RNA, or hnRNA, which is essentially mRNA.
Where is transcription initiated?
Transcription is initiated at the promoter on DNA, whereas translation into protein is initiated at the start codon AUG on mRNA
Which of the following is the sense DNA strand from which the following RNA strand was obtained: 3’-AUCGCUUA-5’?
3’-ATCGCTTA-5’
The sense, or coding, DNA strand has a sequence identical to that of the RNA transcript, except that thymine is replaced by uracil in RNA. Both the sense strand and the RNA transcript are complementary to the antisense, or template, strand from which the RNA was transcribed. Therefore, the correct sequence is the same as that of the RNA molecule but with T in place of U.
What are 4 characteristics of polyadenylation?
It is catalyzed by polynucleotide adenyltransferase.
It provides a binding site for nuclear export proteins.
It protects the 3’ end of mRNA from degradation.
A longer tail leads to a longer period of stability.
The poly(A) tail facilitates binding to nuclear export proteins, which assist with mRNA translocation through pores in the nuclear membrane.
The poly(A) tail protects mRNA from degradation in the cytosol as it migrates from the nucleus to ribosomes within the cytosol.
3-prime exonucleases are primarily responsible for dehydration of mRNA in the cytoplasm. The more adenine residues present at the end of the mRNA molecule, the better defense it has against these exonucleases.
Can prokaryotes undergo alternative splicing?
Prokaryotes do not have introns or exons and therefore cannot undergo alternative splicing.
How does Alternative Splicing work?
During alternative splicing, a complex known as the spliceosome binds to the pre-mRNA and forms a loop. Segments in the loop will be spliced from the mRNA sequence. Here, Segments B (an exon) and C (an intron) will be removed. Contrary to popular misconception, the removal of exons can occur during splicing. In fact, such removal is a primary reason why numerous mRNA transcripts can be generated from a single gene.
In what direction are peptides synthesized?
Proteins are always synthesized from the amino end (N) of the polypeptide to the carboxylate end (C).
How does the Lac Operon work?
The lac operon is a prokaryotic gene cluster that is under the control of a single promoter and operator:
The repressor binds to the operator. RNA polymerase binds to the promoter. Allolactose binds to the repressor to cause it to dissociate. Finally, the CAP protein binds to the CAP binding site.
Why is the Lac Operon referred to as negatively inducible?
It involves a repressor
and
allolactose induces the expression of the structural genes.
The lac operon is a prokaryotic operon that includes genes that encode proteins that metabolize lactose. The lac operon is under negative control, as it involves a repressor. The lac operon is inducible as lactose metabolism is induced (turned on) instead of turned off, by certain environmental conditions.
What are the characteristics of the Trp Operon?
Tryptophan binds the repressor.
The repressor binds the operator.
The presence of tryptophan blocks the genes for its synthesis.
An individual is experiencing symptoms related to the lack of a specific protein. Where would a mutation have to be if there is no mutation in the gene encoding for this protein?
A mutation in the promoter sequence would prevent initiation of transcription entirely, resulting in a total lack of the relevant protein.
What are pre-transcriptional factors and post-transcriptional factors?
Pre-transcriptional factors include: Methylation (gene silencing), Acetylation (gene activating) and other modifications to DNA.
Post-transcriptional factors include: Binding to miRNA
MicroRNA is responsible for post-transcriptional silencing. These short, non-coding RNA molecules bind to mRNA, signaling its destruction or promoting degradation of its protective post-transcriptional modifications.
Why does the genome of intestinal epithelial cells not significantly differ from that of embryonic stem cells from the same individual?
Nearly all cell types within an individual contain the same genome, with some minor differences due to somatic mutation. Rather, it is differential gene expression (from transcription factors, methylation, acetylation, etc) that results in cell morphology and function differences.
What are the Silencer and Enhancer DNA regions?
Silencers and enhancers are eukaryotic regulatory sequences that are bound by repressors and activators, respectively, to regulate the expression of target genes. RNA polymerase initially binds the promoter sequence before transcribing the target gene.
What are the two RNA silencing sequences?
Messenger RNA (mRNA) is single-stranded RNA transcribed from DNA and is translated by ribosomes into protein.
MicroRNA (miRNA) and small interfering RNA (siRNA) are single- and double-stranded RNA sequences, respectively, that target complementary mRNA sequences for destruction, in RNA silencing.
What are examples (3) of prokaryotic gene regulation?
lac operon and trp operon
What location does an oocyte not pass through prior to fertilization?
Uterus
While the oocyte will eventually localize to the uterus, this occurs after fertilization in the Fallopian tubes.
What is an oocyte?
An oocyte is an unfertilized female germ cell.
What is an Ectopic Preganancy?
When a blastocyst normally implants in the uterine endometrium. Any other location of implantation, such as Fallopian tubes or the cervix, is considered to be an ectopic pregnancy.
What are the stages of early embryonic development?
Zygote, morulla, blastocyst, gastrula
- The zygote forms after a fertilization event when the sperm and egg nuclei are combined to make one diploid zygote from the two haploid gametes.
- The zygote undergoes cleavage division as it travels down the Fallopian tubes to the uterus.
- After the 4th cleavage division, when the zygote is at the 16-cell stage, it is a morula.
- The morula continues to divide and develops a fluid-filled cavity (a blastocoel). The outer cell layer surrounding the blastocoel is the trophoblast. At this point, the morula is now known as the blastocyst.
- The blastocyst implants itself in the uterus, where the trophoblast will differentiate to form the placenta, and an inner cell mass at one pole of the blastocoel will undergo gastrulation: the formation of the 3 primary germ layers (endoderm, mesoderm, and ectoderm).
- Once gastrulation begins, the blastocyst is a gastrula.
What is Neurulation?
Neurulation is the embryonic event where the embryo forms a hollow neural tube from the neural plate: a rod of ectoderm cells forms the notochord (an embryonic midline structure that provides both mechanical and signaling cues to the embryo). Then, the formation of the notochord induces the formation of the neural crest just above it from ectoderm cells.
What structures are derived from the Mullerian duct?
Vagina, cervix and uterus
How does sperm fertilize an egg?
The sperm burrows through the corona radiata and latches onto glycoproteins in the zona pellucida. This binding interaction initiates the acrosomal reaction. The sperm remains bound to the glycoproteins of the zona pellucida while it releases digestive enzymes to tunnel through the zona pellucida and permits entry of the sperm nucleus into the egg.
What are the end products (3) of gastrulation?
Ectoderm, endoderm, mesoderm
What is a Blastocoel?
The blastocoel (a fluid-filled cavity in the blastula) forms during blastula development. This is a process that precedes gastrulation, the formation of three germ layers.
What is the correct order of enzymes in the Energy Payoff Phase of the Glycolysis Pathway?
Enzymes in the energy payoff phase of glycolysis (in order):
G3P dehydrogenase
Phosphoglycerate kinase
Phosphoglycerate mutase
Enolase
Pyruvate kinase
The energy payoff phase begins with the conversion of G3P into 1,3-bisphosphoglycerate, catalyzed by G3P dehydrogenase.
Next, phosphoglycerate kinase converts 1,3-bisphophoglycerate into 3-phosphoglycerate by transferring a phosphate group to generate a molecule of ATP.
After that, phosphoglycerate mutase converts 3-phosphoglycerate into 2-phosphoglycerate, which is quickly turned into phosphoenolpyruvate by the enzyme enolase.
Lastly, pyruvate kinase converts phosphoenolpyruvate into pyruvate, generating one more ATP.
What molecules inhibit Pyruvate Kinase?
Molecules that inhibit pyruvate kinase: ATP, Acetyl-CoA and Long chain fatty acids
What organisms exhibit Ethanol Fermentation?
Both prokaryotes and eukaryotes.
Although ethanol fermentation is much more common among prokaryotes than eukaryotes, certain eukaryotes can perform these reactions. The most notable example is yeast, which are single-celled eukaryotes that produce ethanol through ethanol fermentation. They are used to generate fermented food products, like alcoholic beverages.
Does decarboxylation occur during ethanol fermentation?
Yes, the first reaction of ethanol fermentation is a decarboxylation reaction.
The enzyme pyruvate decarboxylase cleaves a carbon from pyruvate, releasing it as a molecule of CO2. Oxidation-reduction (redox) reactions involve electron transfer between two species. This description fits the second reaction of ethanol fermentation, in which alcohol dehydrogenase converts acetaldehyde into ethanol. Acetaldehyde gains electrons and gets reduced, while NADH loses electrons and becomes oxidized.
What are the enzymes associated with Ethanol Fermentation and Lactic Acid Fermentation?
Pyruvate decarboxylase and alcohol dehydrogenase are associated w/ Ethanol Fermentation.
Lactic Acid Fermentation consists of a single reaction: the conversion of pyruvate to lactic acid by the enzyme lactate dehydrogenase. In the process, NADH is oxidized to NAD+.
What is gluconeogenesis used for?
Replenishing glycogen lost in the liver.
Liver cells are responsible for maintaining blood glucose levels within a narrow range. When blood glucose gets too low, they release glucose from storage. However, prolonged fasting and intense exercise deplete the liver’s glucose reserves. Liver cells must make new glucose through gluconeogenesis to replenish their glucose reserves and send glucose molecules out into the bloodstream.
Liver cells quickly burn through their glycogen during periods of fasting and physical activity. They must carry out gluconeogenesis to generate glucose and replace the glycogen that was lost.
What reversible substrates are involved in gluconeogenesis and in glycolysis?
Substrates that are in glycolysis/gluconeogenesis that are reversible are:
Glucose 6-phosphate, Fructose 1,6-bisphosphate and Phosphoenolpyruvate
What are gluconeogenic compounds?
Gluconeogenic substrates include:
Glycine, Alanine, Glycerol and Lactate
because they can all be converted into pyruvate.
What are gluconeogenic organs?
Liver and kidney.
Because liver cells regulate blood glucose levels and store most of the body’s extra glucose, they are also responsible for generating a lot of new glucose molecules through gluconeogenesis. The liver is not the only organ that regulates to blood glucose homeostasis. The kidneys reabsorb glucose from the urine and even create some of their own glucose through gluconeogenesis.
What molecules inhibits inhibit Fructose 1,6-Bisphosphatase?
Molecules inhibiting fructose 1,6-bisphosphatase include:
AMP and Fructose 2,6-bisphosphate
Does Gluconeogenesis occur in all body tissues like Glycolysis?
No, Gluconeogenesis does not occur in all body tissues like Glycolysis does. It is mainly confined to liver and kidney cells, which are in charge of blood glucose homeostasis.
What are all the regulated reactions in Gluconeogenesis?
Regulated reactions in gluconeogenesis:
Fructose 1,6-bisphosphate + H2O → fructose 6-phosphate
Oxaloacetate → phosphoenolpyruvate
What are the reactant molecules in Glycolysis?
ATP and ADP are reactants in glycolysis. ATP is a reactant in two steps of the energy investment phase: the conversion of glucose to glucose 6-phosphate and the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate.
ADP is a reactant in two of the later reactions of glycolysis, during the energy payoff phase. In step 7, phosphoglycerate kinase converts 1,3-bisphosphoglycerate into 3-phosphoglycerate, which requires ADP in order to produce ATP. In step 10, the enzyme pyruvate kinase utilizes ADP to produce another molecule of ATP.
What are the reversible reactions in Gluconeogenesis?
Every other reaction than reactions 1, 3 and 10.
Which steps in the Citric Acid Cycle generate NADH?
Steps 3, 4, and 10 of the CAC generate NADH.
Three NADH are generated in one turn of the citric acid cycle through three key redox reactions all catalyzed by dehydrogenase enzymes. The first is the third step of the cycle, in which isocitrate is converted to alpha-ketoglutarate. In the subsequent step, the conversion of alpha-ketoglutarate to succinyl CoA generates another molecule of NADH. Lastly, NADH is produced in the final step of the citric acid cycle, in which malate is turned into oxaloacetate.
Which steps in the Citric Acid Cycle generate GTP?
Step 5
Only one citric acid cycle reaction generates GTP, and that is the conversion of succinyl CoA to succinate, which is catalyzed by succinyl CoA synthetase. The high energy thioester bond of succinyl CoA is key to producing high energy GTP.
Which steps in the Citric Acid Cycle generate FADH2?
Step 6
In the next step, succinate dehydrogenase transforms succinate into fumarate, reducing a molecule of FAD to FADH2.
What does SDS do?
SDS (Sodium Dodecyl Sulfate) is an amphipathic detergent, containing both polar and nonpolar regions, that disrupts hydrophobic interactions in a protein, which results in disrupted protein folding.
How does temp, pH and CO2 concentration change with a left/right-shift in an hemoglobin-oxygen dissociation curve?
Right-shift
Decreased affinity for O2, increased partial CO2 pressure, increased pH, increased 2,3-BPG and increased temperature
Left-shift
Increased affinity for O2, decreased partial CO2 pressure, decreased pH, decreased 2,3-BPG and decreased temperature and increased Fetal Hemoglobin affinity for O2
How does 2,3-BPG affect affinity of hemoglobin for oxygen and the hemoglobin-oxygen saturation curve?
2,3-BPG reduces the affinity of hemoglobin for oxygen, which facilitates more effective oxygen delivery to the tissues. This corresponds to a rightward shift in the dissociation curve. In the presence of this compound, at a given partial pressure of oxygen, a comparatively low percentage of hemoglobin will be saturated with oxygen.
What is a Gap Junction?
Gap junctions are created by connexin proteins, which create small pores between cells to allow the exchange of solutes between them.
What does a Cadherin do?
Cadherins help connect cells to other cells through adherens junctions and desmosomes.
What does an Integrin do?
Integrins bind cells to their extracellular matrix by connecting cytoskeletal filaments inside the cell to matrix proteins outside the cell.
How does G-actin turn into F-actin?
G-actin units polymerize end-to-end in the cytosol to form the polymer F-actin. A single microfilament typically consists of two F-actin strands. Actin polymerization takes place in the cytosol. G-actin subunits polymerize in a linear fashion, with one subunit adding sequentially to the next. Microfilaments usually contain two strands of F-actin that wrap around each other horizontally.
Which carbon # completes the glycosidic bond/ring structure?
The anomeric carbon, carbon-1 (bearing an aldehyde group in its straight chain form), can be attacked by a hydroxyl group in order to form a ring structure. In the ring form of D-glucose, carbon-1 will participate in glycosidic linkages to other sugars.
What is the organization of Muscle down to Sarcomere?
Muscle, Muscle Bundle, Fascicle, Muscle Fiber, Myofibril, Sarcomere
What are the steps for muscle contraction?
Acetylcholine binds the postsynaptic receptor
Influx of sodium ions from the extracellular environment
Release of calcium from the sarcoplasmic reticulum
Conformational change of tropomyosin
Binding of myosin to Actin
What are the steps in Sliding Filament Theory?
Once ATP is bound to the myosin head it can be hydrolyzed (by myosin), moving it in the cocked position. Once this occurs, calcium ions bind to troponin within the tropomyosin complex, revealing the myosin binding sites on actin. Bound myosin then releases the inorganic phosphate, initiating the power stroke. The myosin stays bound to the actin filament until a new ATP molecule binds to it, releasing it from actin.
What is the structure of a Wax?
Waxes consist of a mixture of fatty acid esters formed from long chain alcohols, aromatic compounds, and other diverse functional groups. The easiest way to recognize the structure above as a wax is through process of elimination. It is clearly a fatty acid derivative but does not have the correct functional groups to qualify as a phospholipid, sphingolipid, or triglyceride.
What is the structure of a Sphingolipid?
Sphingolipids are signaling lipids derived from sphingosine, which is an amine alcohol group. The sphingolipid depicted is a ceramide: the simplest class of sphingolipids.
