Exam 3 Fall 2021 Dr Coffield

The accompanying figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Which of the following statements best explains the low rate of photosynthesis at 550 nm? (picture)

Chlorophyll a does not absorb 550 nm light well

Which of the following statements best describes what happens to a molecule of NAD + (nicotinamide adenine dinucleotide) when it gains a hydrogen atom?

NAD+ becomes reduced.

Which of the following is the most likely effect on the rates of ATP and CO 2 production if yeast cells growing in minimal medium lacking glucose are provided with supplemental acetyl-CoA? (picture)

The rates of ATP production and carbon dioxide production would both increase.

Which of the following describes the function of the pigment molecules in a light-harvesting complex in the thylakoid membranes?

They absorb and transfer light energy to the reaction-center chlorophyll.

Glycolysis results in the net production of which of the following sets of molecules per glucose molecule?

2 NADH, 2 pyruvate, and 2 ATP

Which of the following factors would tend to increase membrane fluidity?

a greater proportion of unsaturated phospholipids

On a spaceship designed to support a multiyear voyage to the outer planets of the solar system, plants will be grown to provide oxygen and to recycle carbon dioxide. Because the spaceship will be so far from the sun, an artificial light source will be needed to support photosynthesis. Which of the following wavelengths of light should be used to maximize plant growth?

a mixture of blue and red light

A newly discovered unicellular organism isolated from acidic mine drainage is found to contain a cell wall, a plasma membrane, two flagella, and peroxisomes. Based on this information only, the organism is most likely to be ________.

a motile eukaryote

Which of the following processes is used by white blood cells when engulfing bacteria?

phagocytosis

In a plant, which of the following reactions produces molecular oxygen (O 2)?

the light reactions alone

Which of the following parameters is most likely to limit the maximum size of a cell?

the ratio of surface area to volume of cytoplasm

Which of the following statements best supports the claim that glycolysis is likely one of the first metabolic pathways to have evolved?

It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.

Which of the following statements best describes the accompanying figure? (picture)

It represents a C4 photosynthetic system.

In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the net production of which of the following sets of molecules?

ATP, CO2, and ethanol

Which of the following organelles often occupy the majority of the volume of a plant cell?

central vacuole

The light reactions supply the Calvin cycle with ________.

ATP and NADPH

Which of the following statements best describes the relationship between autotrophs and heterotrophs?

Autotrophs produce their organic molecules from CO 2 and other inorganic molecules, whereas heterotrophs obtain their organic molecules from compounds produced by other organisms.

New biosensors, applied like a temporary tattoo to the skin, can alert endurance athletes that they are about to "hit the wall" and will find it difficult to continue exercising. These biosensors monitor lactate present in sweat during strenuous exercise. Which of the statements below best explains the use of lactate as an indicator of exercise capacity?

During anaerobic respiration, lactate levels increase when muscles cells need more energy; however, muscles cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration.

Which of the following statements best describes a characteristic feature of a carrier protein in a plasma membrane?

It exhibits specificity for a particular type of molecule.

Which of the following statements best describes a characteristic feature of diffusion?

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is ________.

O2

What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?

The cell will swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.

Which of the following statements best explains the observation that proton pumps are used by organisms in every domain of life?

Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.

Which of the following statements best describes how unsaturated fatty acids increase membrane fluidity at lower temperatures?

The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.

Celery stalks that are immersed in fresh water for several hours become stiff. Which of the following statements best explains the observation that similar stalks left in a 0.15 M salt solution become limp?

The fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal "inside out" to form small vesicles. The fact that these vesicles can transfer electrons from NADH to oxygen and synthesize ATP suggests that which of the following components must be present?

all of the electron transport system and ATP synthase

Which of the following types of metabolic poison would most directly interfere with glycolysis?

an agent that closely mimics the structure of glucose but is not metabolized

A defect in which of the following molecules would dramatically reduce the rate of diffusion of water across cell membranes?

aquaporins

Which of the following occurs during the Calvin cycle?

carbon fixation

An animal cell that lacks carbohydrates on the external surface of its plasma membrane would likely be impaired in which of the following functions?

cell-cell recognition

The synthesis of ATP by oxidative phosphorylation is an example of which of the following processes?

coupling of an endergonic reaction to an exergonic reaction

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through which of the following structures?

gap junctions

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?

glycolysis

Asbestos is a material that was extensively used in construction for decades. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will take up asbestos by phagocytosis, but are not able to degrade it. Toxicity most likely results from accumulation of asbestos in which of the following organelles?

lysosomes

A young child who suffers from a metabolic disease is always tired and fatigued. Which of the following organelles is most likely malfunctioning in this disease?

mitochondria

Cyanide binds with at least one protein complex involved in producing ATP. If a cell is exposed to cyanide, most of the bound cyanide is likely to be localized within which of the following organelles?

mitochondria

A person on a strict diet and exercise regimen lost 7 kg (about 15 pounds) of body fat in just two weeks. In which of the following forms did the lost fat most likely leave the body?

released as CO2 and H2O

A newly synthesized protein destined for secretion from a eukaryotic cell will generally follow which of the pathways listed below?

rough ER → Golgi → transport vesicle → plasma membrane

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is abundant in liver cells and primarily responsible for detoxification processes?

smooth endoplasmic reticulum

Which of the following is the most appropriate technique for observing and measuring the size of ribosomes in a eukaryotic cell?

transmission electron microscopy