Download BIOL 1408 EXAM 2,Lone Star College System and more Exams Biology in PDF only on Docsity!
Points Awarded 47.
Points Missed 3.
Percentage 94.0%
A scientist claims to have created a machine that can run forever, therefore producing as much energy as it consumes. This claim violates: A) The first law of thermodynamics B) The second law of thermodynamics C) The third law of thermodynamics D) The law of endergonic reactions E) The law of exergonic reactions
Feedback: According to the second law of thermodynamics, when energy is converted from one form to another, some is always "lost" (made unusable) in the form of heat. No energy transformation is 100% efficient. Points Earned: 0.0/1. Correct Answer(s): B
Why is ATP used as the energy currency in cells? A) ATP carries a positive charge B) ATP contains energy stored in the phosphate bonds C) ATP is made directly from glucose D) ATP is a macromolecule E) ATP is made from lipids
Feedback: ATP is a nucleotide with three phosphate groups, and easily loses the last phosphate group to release energy. When ATP breaks down to ADP + P, energy is released. Points Earned: 1.0/1. Correct Answer(s): B
ATP is made up of:
A) Adenine, ribose, and one phosphate B) Adenine, ribose, and three phosphates C) Adenine and three phosphate groups D) Adenine and two phosphate groups E) Adenine and one phosphate group
Feedback: ATP, adenosine triphosphate, means that it contains the sugar ribose, the nitrogen-containing base adenine, and three phosphate groups. Points Earned: 1.0/1. Correct Answer(s): B
Which of the following statements about enzymes is false? A) They speed up chemical reactions. B) They are not reusable. C) They are proteins. D) They are reusable. E) They are considered organic catalysts.
Feedback: Enzymes are reusable, they are not destroyed permanently altered by their participation in the reactions they catalyze. Points Earned: 1.0/1. Correct Answer(s): B
How can enzymes speed up chemical reactions? A) They lower the rate of ATP breakdown in the reaction. B) They increase the amount of substrate in the reaction. C) They lower the activation energy needed for the reaction. D) They increase the pH of the reaction. E) They lower the temperature of the reaction.
Feedback: Enzymes lower the energy of activation by bringing reactants together in an effective way at body temperature. Points Earned: 1.0/1.
Points Earned: 1.0/1. Correct Answer(s): D
What does "B" represent in the diagram of the plasma membrane? A) hydrophilic heads B) peripheral protein C) phospholipids bilayer D) cytoskeleton E) glycolipid
Feedback: Refer to Figure 5.8 and discussion about the plasma membrane on page 93. credit given, poor quality illustration Points Earned: 1.0/1. Correct Answer(s): D
What does "E" represent in the diagram of the plasma membrane?
A) cytoskeleton B) peripheral protein C) phospholipids bilayer D) hydrophilic heads E) glycolipid
Feedback: Refer to Figure 5.8 and discussion about the plasma membrane on page 93. credit given, poor quality illustration Points Earned: 1.0/1. Correct Answer(s): E
Which is the correct association of cell membrane protein types? A) Receptor proteins : have a binding site for a specific molecule B) Channel proteins : assist in cell-to-cell communication C) Carrier proteins : carry out metabolic reactions D) Enzymatic proteins : allow molecules to move across membrane E) Cell recognition proteins : help substance move across the cell membrane
Feedback: Channel proteins allow passage of molecules, and carrier proteins assist the passage of molecules through the membrane. Cell recognition proteins are glycoproteins that help the body recognize foreign invaders. Receptor proteins bind specific signaling molecules. Enzymatic proteins carry out metabolic reactions. Junction proteins assist cell-to-cell communication. Points Earned: 1.0/1. Correct Answer(s): A
When chloride ions cannot cross through the plasma membrane, what disease does the patient have? A) Type 2 diabetes B) Huntington's disease C) Color blindness D) Cystic fibrosis E) Type 1 diabetes
Feedback: Cystic fibrosis is due to a defect in the chloride channel protein.
Correct Answer(s): B
What is the reverse process of endocytosis called? A) Phagocytosis B) Pinocytosis C) Active transport D) Osmosis E) Exocytosis
Feedback: Bulk transport occurs when fluid or particles are brought into a cell by vacuole formation, called endocytosis, or out of a cell by evagination, called exocytosis. Points Earned: 1.0/1. Correct Answer(s): E
What are the membrane-lined channels that allow direct exchange of materials between two adjacent plant cells? A) Anchoring desmosome B) Intermediate filament C) Plasmodesmata D) Extracellular matrix E) Tight junctions
Feedback: Living plant cells are connected by plasmodesmata. Cytoplasmic strands within these plasmodesmata channels allow direct exchange of some materials between adjacent plant cells Points Earned: 1.0/1. Correct Answer(s): C
Which of the following statements is not true of autotrophs? A) They must take in organic matter to make energy. B) They produce their own food. C) Plants are autotrophs.
D) They convert light energy into chemical energy. E) Cyanobacteria are autotrophs.
Feedback: Autotrophs, which include plants and cyanobacteria along with algae, produce their own food by capturing the energy of sunlight and converting into chemical energy. Unlike heterotrophs, they do not need to take in organic matter for an energy source. Points Earned: 1.0/1. Correct Answer(s): A
A biologist wants to study heterotrophs. Which of the following organisms would he or she be most interested in studying? A) Producers B) Autotrophs C) Plants D) Algae E) Consumers
Feedback: Consumers are heterotrophs: They consume food made by autotrophic, producer organisms, such as plants and algae. Points Earned: 1.0/1. Correct Answer(s): E
Which of the following organisms use organic molecules produced by photosynthesis? A) Autotrophs only B) Heterotrophs only C) Heterotrophs and autotrophs D) Only plants and algae E) Only animals
Feedback: The organic molecules produced by photosynthesis feed not only the autotrophs which make them (such as plants and algae), but also heterotrophs (such as animals). Points Earned: 1.0/1. Correct Answer(s): C
This figure shows a plant chloroplast. What does "a" represent? A) Oxygen B) Water C) Glucose D) Carbon dioxide E) ATP
Feedback: Carbon dioxide enters leaves through stomata and reaches the stroma of the chloroplast by diffusion. There, it is reduced to carbohydrate by the reactions of the Calvin cycle. Points Earned: 1.0/1. Correct Answer(s): D
The reason why most leaves are green is that they absorb the green wavelengths of light. A) True B) False
Feedback: Chlorophyll, the pigment that gives leaves their green color, does not absorb green wavelengths of light. Rather, it transmits or reflects green wavelengths. Points Earned: 1.0/1. Correct Answer(s): False
Why is water split during photosynthesis? A) To replace the electron lost in photosystem II B) To replace the electron lost in the first electron acceptor
C) To replace the electron lost in the second electron acceptor D) To replace the electron lost in photosystem I E) To replace the electron lost in the electron transport chain
Feedback: In the noncyclic electron pathway, an excited electron leaves photosystem II and does not return. To replace the lost electron, a molecule of water is split. Points Earned: 1.0/1. Correct Answer(s): A
The method of turning ADP into ATP is called chemiosmosis because ATP production is tied to a hydrogen ion gradient across a membrane. A) True B) False
Feedback: In addition, water is produced when the hydrogen ions rejoin electrons and oxygen after crossing the membrane through ATP synthase. Points Earned: 1.0/1. Correct Answer(s): True
The major goal of the Calvin cycle is to produce which of the following? A) ATP B) Carbohydrate C) NADPH D) RuBP E) NADP+
Feedback: The Calvin cycle functions to fix carbon dioxide and convert it to carbohydrate. ATP, NADPH, and RuBP are all necessary in order for the Calvin cycle to function. NADP+^ is produced as NADPH is oxidized during the Calvin cycle, but this molecule returns to the light reactions. Points Earned: 1.0/1. Correct Answer(s): B
This situation is ideal for C 3 photosynthesis. C 4 and CAM photosynthesis are specialized for environments where plants must often keep stomata closed to conserve water. Points Earned: 1.0/1. Correct Answer(s): C
Which of the following statements is false about C 4 plants? A) They are specialized for environments with moderate temperatures and rainfall. B) Their mesophyll cells are arranged in parallel rows. C) They have chloroplasts in their mesophyll and bundle sheath cells. D) They work efficiently at low levels of carbon dioxide. E) They work efficiently at low levels of water.
Feedback: C 4 plants are specialized for warmer, drier conditions than C 3 plants. Points Earned: 1.0/1. Correct Answer(s): A
This figure shows a cross section of a typical plant leaf. What does "b" represent? A) The mesophyll B) A stoma C) A leaf vein D) The upper epidermis E) The cuticle
Feedback: The upper epidermis is represented by "d." See Figure 6.2. Points Earned: 1.0/1. Correct Answer(s): D
What is the effect of burning trees on atmospheric levels of carbon dioxide? A) Carbon dioxide levels increase because trees would ordinarily absorb carbon dioxide. B) Carbon dioxide levels decrease because trees ordinarily produce carbon dioxide. C) Carbon dioxide levels are unaffected because plants are not involved in carbon dioxide fixation. D) Carbon dioxide levels increase because the rate of photosynthesis increases. E) Carbon dioxide levels are unaffected because forests do not make a significant contribution to global carbon dioxide fixation.
Feedback: Carbon dioxide levels increase because plants, including trees, absorb large amounts of carbon dioxide from the atmosphere. Burning trees not only releases carbon dioxide, but also reduces the number of trees available for carbon dioxide absorption. Even though forests, tropical rainforests in particular, are shrinking worldwide, they still make a substantial contribution to carbon dioxide fixation. Points Earned: 1.0/1. Correct Answer(s): A
Which of the following phases takes place entirely outside the mitochondria and is considered to be anaerobic? A) Electron transport chain B) Preparatory reaction C) Glycolysis D) Krebs cycle E) Chemiosmosis
Feedback: Glycolysis occurs entirely in the cytoplasm and does not require the presence of oxygen. Points Earned: 1.0/1. Correct Answer(s): C
As a result of glycolysis, one molecule of glucose is broken into two molecules of A) pyruvate. B) NADH. C) acetyl CoA. D) FADH 2.
A) FADH 2
B) Carbon dioxide C) NAD+ D) ATP E) NADH
Feedback: The coenzyme NAD+^ is an important input for the Krebs cycle, as the breakdown product of glucose is rearranged and oxidized, NAD+^ is reduced to NADH. NADH carries electrons to the electron transport chain. Points Earned: 1.0/1. Correct Answer(s): C
The Krebs cycle occurs four times per glucose molecule. A) True B) False
Feedback: The Krebs cycle occurs two times per glucose molecule. Points Earned: 1.0/1. Correct Answer(s): False
What is the significance of the cristae in the mitochondria? A) Increase surface area therefore increasing glycolysis B) Increase surface area therefore increasing the Krebs cycle C) Increase surface area therefore increasing the preparatory reaction D) Increase surface area therefore increasing fermentation E) Increase surface area therefore increasing the electron transport chain
Feedback: Since the cristae increase the surface area of the inner membrane, they increase the space available for electron transport chain carriers. Points Earned: 1.0/1. Correct Answer(s): E
What role does oxygen play in cellular respiration? A) It acts as the final electron acceptor in the electron transport chain. B) It acts as a coenzyme in the electron transport chain. C) It acts as an input for the Krebs cycle. D) It acts as an input for glycolysis. E) It acts as an intermediate between glycolysis and the Krebs cycle.
Feedback: The role of oxygen in cellular respiration is to serve as the ultimate electron acceptor at the end of the electron transport chain. Points Earned: 1.0/1. Correct Answer(s): A
During the electron transport chain ATP is made through the process of chemiosmosis. This ATP- producing process is called chemiosmosis because it is powered by the flow of hydrogen ions moving down their concentration gradient through the ATP synthase complexes located in the mitochondrial cristae. A) True B) False
Feedback: This ATP-producing process is called chemiosmosis because it is powered by the flow of hydrogen ions moving down their concentration gradient through the ATP synthase complexes located in the mitochondrial cristae. Points Earned: 1.0/1. Correct Answer(s): True
What would be the result if oxygen became unavailable to the cell? A) Glycolysis would stop. B) The Krebs cycle would stop. C) The electron transport chain would stop. D) The preparatory reaction would stop. E) Substrate-level ATP synthesis would stop.
Feedback: The electron transport chain would stop because it depends on oxygen to serve as the final electron acceptor.
C) gain weight because intermediates from cellular respiration can be converted to fat. D) gain weight because you will retain water. E) lose weight because you will become dehydrated.
Feedback: Consuming large amounts of carbohydrates results in a surplus of fuel for cellular respiration. The excess G3P from glycolysis and acetyl groups from the preparatory reaction are used to form fatty acids, necessary for fat synthesis. Points Earned: 1.0/1. Correct Answer(s): C
If a baker wants to make bread, which of the following organisms must be used to make the dough rise? A) Saccharomyces cerevisiae B) Lactobacillus C) Acetobacter aceti D) Streptococcus thermophilus E) Aspergillus
Feedback: Baker's yeast,Saccharomyce cerevisiae, is added to bread for the purpose of leavening—the dough rises when the yeasts give off CO 2. Points Earned: 1.0/1. Correct Answer(s): A
This figure shows the relationship between the chloroplast and the mitochondrion. What does "a" represent? A) Carbon dioxide B) Water C) Oxygen D) Carbohydrates E) ATP
Feedback: Photosynthesis in the chloroplast releases oxygen, and aerobic respiration in the mitochondrion requires oxygen. Points Earned: 1.0/1. Correct Answer(s): C
