Lecture Exam Flashcards
Transport of ions and water across cell membranes occurs through:
the lipid bilayer.
through crevices in the membrane.
through protein pores called channels.
by endocytosis.
through protein pores called channels.
(Protein pores span the lipid bilayer and provide a selective pathway for small ions and water. Endocytosis allows transport of larger molecules.)
The equation 6CO2 + 6H20 + energy => C6H12O6 + O2 represents the overall reactions of
photosynthesis
respiration
glycolysis
Krebs cycle
photosynthesis
A(n) _______________ forms when two atoms share electrons.
covalent bond (A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs and the stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.)
Many pharmaceutical drugs like ibuprofen work by
inhibiting absorption of substances
inhibiting respiration
inhibiting enzymes
stimulating respiration
inhibiting enzymes (Many drugs interfere with metabolic pathways by inhibiting enzymes. Ibuprofen, for example, inhibits the enzyme cyclo-oxygenase 2. )
Which of the types of cellular activities listed below would not use ATP?
protein synthesis
muscular contraction
active transport
flagella movement
passive transport
Passive transport (Cells use ATP to carry out nearly all of their activities including active transport, muscle contraction, flagella movement, protein synthesis, and many others. Passive transport requires no cellular energy for it to occur as it moves materials across the cell membrane with the concentration gradient).
If the pH of a solution is 6, the concentration of hydroxyl ions (OH-) is ___________________.
10-8M
8M
6M
10-6M
10-8M (The ionic product of H+ and OH- is constant at 10-14M. If the H+ concentration is 10-6M (pH=6), the concentration of OH- ought to be 10-8M.)
Blood pH is kept between 7.35 and 7.45 by the CO2/Bicarbonate buffering system. What organs control levels of CO2 and bicarbonate, respectively?
lungs and liver
lungs and kidneys
kidney and lungs
liver and lungs
lungs and kidneys,
Eukaryotic cells respire glucose more efficient than prokaryotic cells. This is because of the presence which organelle?
glucose transporters
nucleus
chloroplasts
mitochondria
mitochondria, “Mitochondria increase the energy efficiency of glucose by further oxidizing its electrons and producing more ATP.”
The figure below reflects how these two cells would respond in a(n) ________ environment.
isotonic
diffuse
hypotonic
hypertonic
ionic
hypertonic, Water moves from an area of greater concentration of water to an area of lesser concentration of water. Since water is moving out here, the medium of these cells must have less water/be more concentrated, i.e., hypertonic.
Agent orange and insecticides cause hyperventilation and are eventually lethal because they _______________________.
uncouple glycolysis from the Krebs cycle
release too much oxygen from mitochondria
uncouple respiration from energy production.
trap oxygen in mitochondria
uncouple respiration from energy production.
Amino acids are the primary building blocks of ________________________.
polysaccharides
proteins
nucleic acids
lipids
proteins
The process by which cells secrete substances into the extracellular fluid is called
secretion
endocytosis
diffusion
exocytosis
exocytosis, (During exocitosis, vesicles containing secretion material fuse to the cell membrane, ensuing release of certain substances like digestive enzymes and hormones.
Pepsin and trypsin are digestive enzymes that hydrolyze proteins at different pH. Which of the following statements is correct?
The functional (quaternary) shape of these enzymes is achieved at different pHs.
The enzyme-substrate interaction is optimal at different pHs.
Pepsin digests proteins in the stomach, while trypsin digests proteins in the small intestine.
All of the alternatives are correct.
None of the alternatives is correct.
All of the alternatives are correct.
Carotenoids are found in high concentrations in yellow and orange leaves or vegetables. This color is seen because the carotenoid pigments
absorb or transmit yellow and orange wavelengths of light.
absorb all wavelengths of light and then transmit yellow and orange wavelengths.
absorb yellow and orange wavelengths of light.
absorb or reflect yellow and orange wavelengths of light.
reflect and transmit yellow and orange wavelengths of light.
reflect and transmit yellow and orange wavelengths of light. (The colors that are seen from pigments are due to the reflection of transmission of those wavelengths of light. All others are absorbed)
The O2 given off during photosynthesis is derived from which compound?
H2O
CO2
RuBP
NADP+
CO2 and H2O
H2O, The “leftover” from the splitting of water is ½O2, which combines to form O2.
The figure below is depicting the interaction of water molecules with one another, which involves the use of
ionic bonds.
no chemical bonding.
hydrogen bonds.
positive and negative ions.
covalent bonds.
hydrogen bonds, The positive hydrogen forms a hydrogen bond with the negative oxygen from a nearby molecule. No electron transfer or sharing is occurring in this type of bond. It is a weak attraction between polar molecules.
In feedback inhibition of a metabolic pathway, where does the inhibitor bind?
to the substrate of the first reaction
to a substrate or the product of the last reaction
to the product of the first reaction
to the enzyme of the first reaction
to the enzyme of the last reaction
to the enzyme of the first reaction, In feedback inhibition, the final product binds to the first enzyme, either at the active site or at another site.
Digestion of starch and proteins yields _________________________ and _________________________________, respectively, which are then absorbed in the ________________________.
nucleic acids, glucose, large intestine
glucose, aminoacids, small intestine
glycogen, aminoacids, small intestine
glucose, aminoacids, large intestine
glucose, aminoacids, small intestine
Heart arrhythmia or fibrillation can be caused by defects in ______________________.
A.
none of the alternatives
B.
Anchoring junctions
C.
Tight junctions
D.
Gap junctions
Gap junctions, A defect in GAP junctions may delay the spread of contraction signals and cause the heart cells to contract disorderly.
The cellular organeles resposible for “packing and shipping” of proteins inside the cells are:
the endoplasmic reticulum and Golgi apparatus
mitochondria and chloroplasts
nucleus and endoplasmic reticulum
vacuoles and peroxysomes
the endoplasmic reticulum and Golgi apparatus
The figure below represents a metabolic pathway. What happens if Enzyme2 is defective and nonfunctional?
Product Z would increase in amount.
Substrate Y would not be metabolized.
Substrate X is destroyed.
Substrate X would not be metabolized.
Substrate X would increase in amount.
Substrate Y would not be metabolized.
Substrate Y is the product made from substrate X with the assistance of Enzyme1. It is also the reactant that would not be able to form the end product if Enzyme2 were defective.
The studded dark structures in the rough endoplasmic reticulum (see below) allow for ______________________________.
protein translation into the lumen.
calcium transport into the lumen.
proteins to be released from the lumen
calcium release from the lumen
protein translation into the lumen.
(the studded structures are ribosomes, which translate messenger RNA into primary polypeptide structures which are further modified in the lumen of the ER.)
Molecules in living organisms are mainly composed of the following chemical elements:
C,H,O,N
S,H,O,N
Na, K, Cl, H
none of the alternatives
C,H,O,N
N,O,H,C or CHON backwards makeup proteins, lipids, carbohydrates, and nucleic acids.
The glycoproteins found in the plasma membrane function in what capacity?
to attach to the cytoskeleton on the interior of the cell and maintain the cell in a position relative to other cells
to maintain the membrane’s fluidity
to transport molecules across the membrane
to catalyze reactions that are crucial to the cell’s functioning
to allow one cell to recognize another of the same type or from the same body
to allow one cell to recognize another of the same type or from the same body,
The carbohydrate portions of a glycoprotein will match to receptor proteins on another cell so that the origin of the cell can be established.
Chlorophyll is to the light reactions as ________ is to the Calvin cycle.
RuBP
ATP
ATP synthase
NADP+
carbon dioxide
RuBP, Chlorophyll accepts input (solar energy) and funnels that energy in the form of electrons into production of the end products of the light reactions (ATP and NADPH). In the process, chlorophyll is regenerated. Likewise, RuBP accepts input (CO2) and energy from the light reactions to produce the end product of the Calvin cycle (G3P). RuBP is then regenerated.
The concentration of calcium in a cell is 3%. The concentration of calcium in the surrounding fluid is 1%.
How could the cell obtain more calcium?
diffusion
active transport
passive transport
osmosis
pinocytosis
active transport, Active transport could be used to assist in moving the calcium in low concentration across the plasma membrane to an area where there is more calcium. This movement would require protein transport carriers and the addition of ATP energy to carry this out.
The image below exemplifies the ____________________ structure of hemoglobin.
quaternary
primary
secondary
tertiary
quaternary
