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Biology

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Which if the following represents the sequence of events during Mitosis?
Prophase-metaphase-anaphase-telophase
Howm many tertads exist in a human cell at prohase 1?
23
A bacterial chromosome consists of?
A circular DNA molecule many times larger than the cell
Eukaryotic chromosomes consist of?
linear DNA molecules that are complexed with positively charged histone proteins
Nucleosomes are best described as?
eukaryotic DNA associated with histone proteins
Each nucleosome has___base pair of DNA wrapped around a disc-shaped core of eight histone molecules?
146
What is the function of nucleosomes?
To prevent DNA stands from tangling
Nucleosomes are organized into large coiled loops in visible chromosomes by?
scaffolding proteins
The cell cycle of a typical somatic cell consists of___ and M (mitosis or meiosis) phase?
Interphase
The M( mitosis or meiosis) phase of the cell cycle involves two main processes?
mitosis and cytokinesis
Once nerve cells become mature, they dont usually undergo cell division. Based on your knowledge of the cell cycle you would predict that mature nerve cells become arrested in the___ of the cell cycle?
G(o) Phase
*note thats the number 0 as a subscribt
Chromosomes are duplicated during____of the cell cycle?
S phase
Mutation( changes in genetic make-up)is the predominant cause for biological evolution?
Glycolysis
Which the name of the first enzyme of glycolysis?
Hexokinase
What is the name of the second enzyme of glycolysis?
Phosphogluco-isomerase
The first enzyme of stage 2 of glycolysis is which of the following?
G-3-P dehydrogenase
Which enzyme catalyzes the transfer of a phosphate group away from a substrate to ADP?
phosphoglycero-kinase and pyruvate kinase
Which enzyme transfers a phosphate group from one carbon to another carbon on the same organic molecule therefore it is which of the following type of enzymes?
mutase
Which enzyme removes water so it is which of the following types of enzymes?
enolase
Which is the last enzyme of glycolysis so it is which of the following?
pyruvate kinase...Anerobic Fermentation
If a cell is in G2?
It has twice the amount of DNA present in one telophase nucleus (there are two nuclei in a telophase cell)
During Prophase,____is/are compacted into visible chromosomes
chromatin
The _____is responsible for the separation of the chromosomes during____ of mitosis?
Sister chromatids; centromers
The mitotic spindle is made of?
microtubes
The kinetichore serves which of the following in functions?
Kinetochores attach to mictotubles during mitosis
All of the following events occur during prometaphase EXCEPT:
the duplicated chromosomes become invisible with the light microscope
A cell is in Metaphase if?
The chromosomes are aligned at the mid plane of the cell
Duplicated centrioles move to opposite poles of a dividing____cell during____of the cell cycle?
animal; prophase
The chromosome makeup of an individual organism is called a?
karyotype
Chromosomes are condensed to their greatest extent during____of mitosis?
Metaphase
Cytokinesis in animal cells involves contraction of a ring of ___microfilaments?
actin plus myosin
Cytokinesis in plant cell mitosis occurs initially by the formation of a(n)?
cell plate
Generation time refers to ?
the time it takes to complete once cell cylce
If a cell is dividing by binary fission then you know that?
the cell is prokaryotic
To prevent disastrous consequences, the eukaryotic cell cycle is controlled by?
a series of cell cycle checkpoints
Which of the following statements concerning the cell cycle is false?
M-cdk inhibts mitosis
The correct number of chromosomes is maintained during sexual reproduction by:
meiosis, which reduces the chromosome number by half
Animal cells are stimulated to divide by mitosis by?
growth factors
If Meiosis did not occur in sexually reproducing organisms, then?
Chromosome number would double in each generation
What evolutionary advantage is provided by sexual reproduction?
increased genetic diversity
Plant clones can be produced by?
Asexual reproduction
Plant hormones known as_____stimulate mitosis?
cytokinins
Most human somatic cells are?
diploid
Homologous chromosomes undergo synapses during?
prophase 1
During prophase 1 of meiosis, homologous chromosomes lie side by side. This phenomenon is know as?
tetrad formation
A maternal homologue and a paternal homolgue synapse form?
a tetrad
During which phase does cross-over occur?
prophase 1
A zygote contains the ____ complement of chromosomes?
diploid
In a human cell at prophase 1, there are____tetrads?
23
An animal with a diploid number of 36 chromosomes will have ____ chromosomes in its gametes and _____chromosomes in its somatic cells?
18;36
During prophase 1, each chiasma represents?
a site of crossing over
During which of the following stages of meiosis do the sister centromeres separates?
anaphase 2
WHich of the following events does not occur in prophase 2?
a formation of chiasmata (no synapsis, no crossing over)
The source of genetic variation during meiosis are?
crossing over and and the random assortment of maternal and paternal chromosomes
Which of the following events does not occur in meiosis 1?
separation of sister chromatids
Prokayrotic DNA Polymerase 3 catalyzes the synthesis of a strand of DNA by bonding deoxyribonucleotides to a nucleotide chane by which type of bond?
Phospodiester
WHich of the following is the mechanism by which DNA is replicated?
Semiconserative
Which of the following statements best described DNA polymerase 3?
It is an enzyme that requires the presence of a small RNA primer to catalyze the additoon of deoxyribonucleotide triphosphates to the 3' hydroxyl end of the chain
Which enzyme is required to to join Okazaki fragments by catalyzing the formation of a phosphodiester bond between them during DNA replication?
hgase
which molecule is responsible for breaking hydrogen bonds to separate double -stranded DNA into single strands?
DNA helicase
WHich of the following produces short sequences of RNA which are complementary to the template DNA in order to allow DNA polymerase to synthesize a new complementary strand of DNA?
DNA Primase
The function of DNA polymerase 3 includes which of the following?
DNA synthesis and proofreading
Which of the following statements is true of membrane phospholipids?
they freely move laterally within the membrane
WHich of the following is Correct about active transport?
It requires energy
After eating a meal, the end products digestion are transported by the blood stream to the liver which contains a large amount of glucogen. Therefore glucose is transported from the bloodstream into liver cell by which of the following?
active transport
What is meant by the term "fluid mosaic model"of membranes?
It is the movement of lipids and integral proteins within the lipid bilayer
What is the main role of the pigment molecules within the antenna of light-harvesting complex?
absorb photons of light energy and transfer them to the reaction center chlorophyll
What is the primary functions of Photosystems 1 and 2?
produce O(2), ATP, and NADPH(2)
Which of the following molecules directly denotates H(+) to convert NADP+ to NADPH(2)?
Ferrodoxin
During noncyclic electron flow of the light reaction, which molecule is the final acceptor of the high-energy electron?
NADP(+)
which molecule is combines with CO(2) to form 3- phosphoglycerate in the calvin cycle?
ribulose 1,5, bisphosphate (RUBP)
The first step in the calvin cycle is the attachment of carbon dioxide to which of the following?
RUBP
Which of the following are products of the light dependent reactions which are required for the dark reaction?
ATP, and NADPH+H
the O(2) produced by photosynthesis comes directly from which of the following?
H(2)O
Which of the following requires both ATP and NADPH(2)?
the calvin cycle
During the first enzyme catalyazed reaction of the calvin cycle, which molecule is bonded with CO(2) to form the 3-carbon substances, 3-phosphoglycerate?
RUBP
In C4 plants, PEP carboxylase catalyzed reactions that fix CO(2) into four carbon compounds occur in which of the following?
Mesophyll cells
At night, CAM plants incorporate CO(2) into which of the following?
malate
Which of the following as the highest photosynthetic efficiency in hot and dry enviornments?
C4 plants
What is true of succlent plants such as cacti or pineapple?
they produce 4 carbon malate in the first step of carbon fixation
When NAD is reduced to NADH+H during glycolysis under aerobic conditions and cellular respiration the pair of hydrogens are transferred from NADH+H to which of the following?
Complex 1 of the electron transport chain
In the absense of O(2) hydrogen atmos generated by glyclysis to form NADH+H are transferred to the end product of glycolysis in which of the following process?
Fermentation
Which of the following is the end product- of glycolysis that is produced by yeast cells grown under anaerobic conditions?
NAD and ethyl alcohol
A single glucose molecule used for cellular respiration can drive how many turns of the Kreb cycle?
2
In Muscle cells fermentation produces which of the following?
lactic acid
Which enzyme catalyze the decaroxylation of pyruvate to form Acetyl CoA
Pyruvate dehydrogenase
Which of the following are produced when pyruvate is decarboxylated during the firs step of cellular respiration?
CO(2), NADH+H and Acetyl CoA
Whar is the first enzyme of the Citric Acid Cycle?
citrate synthetase
Which of the following are substrates for the first enzyme step of turns of the Citiric acid cycle ?
Oxaloacetate, H(2)O and Acetyl CoA
Which of the Citric Acid Cycle substrates are decarboxylated?
Isocitrate and alpha-keto glutarate
How many CO(2) molecules are produced during one turn of the Citric Acid Cycle?
2
How many NAD molecules are reduced to NADH+H during one turn of the citric Acid cycle?
3
Which of the following types of enzymes catalyxes the transfer of a phosphate group from substrate molecule to ADP to form ATP?
kinase
Which of the following enzymes catalyzes the transfer of hydrogens with frutose 1,6 bisphosphate in order to split the substrate into two smaller molecules consisting of 3 carbons each?
aldolase
which of the following types of enzymes catalyzes the transfer of a phosphate group from one carbon on an organic molecule to another carbon on the same molecule?
mutase
which of the following types of enzymes catalyze reactions that transfers hydrogens frome substrate to to NAD or NADP to reduce them to NADH+H or NADPH(2)?
dehydrogenaze
Which carbon number is phospholated during the first enzyme step of glycolysis stage 1?
6
What substrate is the source of the phosphate group that is transferred to glucose and in a later step frutose 6 phospate during phosphorylation enzyme reactions of stage 1 of glycolysis
ATP
WHich of the following are products of stage 1 of glycolysis?
2 G3P and 2 ADP
Which of the following is the first enzyme of stage 2 of glycolysis pathway?
G3P dehydrogenase
Which of the following are the products of stage 2 of glycolysis?
2 ATP, 2 pyruvates and 2 NADH+H
which of the following enzymes catalyzes the transfer of phosphate group ATP to a substrate
Kinase
How many ATP molecules are consumed during stage 1 of the glycolysis for each glucose that centers the pathway?
2
Which of the following enzyme catalyze the reactions that synthesize ATP during glycolysis?
Phospoglycerate kinase and pyruvate kinase
The spindle fibers are composed of which of the following?
Microtubules
Assuming a fatty acid with 12 carbons molecule can be oxidized into acetyl CoA molecules, which are immediately used in the Citric Acid cycle how many ATP can be produced by cellular respiration from this 12 carbon fatty acid molecule ?
102
The primary function of an enzyme or ribozyme or any biological catayst is to do which of the following?
reduce the energy of activation and increase the rate of a reaction
WHich of the following consist of molecular machines that organizes the cell and directs cellular movement?
cytoskeleton
Which portion of the photosynthetic apparatus is involved in the oxidation or splitting of water?
light harvested by chlorophyll
which if the following reduces NADP to NADPH(2)?
light reactions alone
During aerobic respiration the final acceptor of the hydrogen atom at the end of the electron transport chain is which of the following?
O(2)
How many NADH+H molecules are produced from one glucose molecuel, considering only glycolsis and the conversion of pyruvate molecules to acetyl CoA molecules?
four
During one turn of the citric acid (krebs) cycle, each acetyl CoA entering the cycle yields?
1 GTP, 3 NADH and 1 FADH(2)
WHich of the following steps in the Citric Acid Cycle directly produces a molecule of ATP (or GTP)?
succinyl CoA synthesis step
Which of the following is True of the Citric acid cycle?
It yields ATP, NADH, and FADH(2)
How many ATP and NADH molecules are produced from each molecules of glucose in the citric acid cycle?
2 ATP, 6 NADH
Which of the following processes will occur either in the presence or absence of oxygen
glcolysis