Biology Exam 1_PLB 115
Which of these photon wavelengths contains the greatest amount of energy?
gamma rays
The substrate of an enzyme is _____ .
what the enzyme acts on
Gram‑positive bacteria
• Have thick cell walls • have no membrane in the outside of cell walls • all found in one phylum • have lipoteichic acid that anchors the cell walls to the cell membranes
Gram‑negative bacteria
• have thin cell walls • have lipoproteins and lipopolysaccharides in the membranes on the outer side of the cell walls • found in many phyla
Pyruvate is a product of glycolysis and is subsequently converted to acetyl‑CoA. Acetyl‑CoA is a substrate for the citric acid cycle (CAC). Exactly how many molecules of glucose must be oxidized in glycolysis to provide the input for 12 turns of the CAC?
6
How do chlorophyll pigments absorb energy from light?
A photon excites an electron in the chlorophyll to a higher energy state.
Some inherited syndromes, for example MERRF (myoclonic epilepsy with ragged red fibers), interfere with the function of mitochondria. From what you know about mitochondria, why do you think the muscles and the nervous system are the predominant tissues affected in MERRF?
Mitochondria are the most metabolically active and require the most energy.
Receives NADH or FADH2
Oxidative Phosphorylation
Facilitated diffusion is a type of passive transport that allows solutes to move across the plasma membrane of a cell. Which statements describe facilitated diffusion?
Solutes move across the membrane down their concentration gradient through specialized membrane proteins. Small, charged molecules and ions move down their concentration gradient into a cell through proteins in the plasma membrane.
Water is moving across a membrane from solution A into solution B. What can be inferred?
Solution A must have a lower solute concentration than Solution B.
You find a single-cell organism with a cell wall in the soil of a forest—can this organism be an animal? Which characteristics indicate that the organism is a bacterium and not a plant?
The cell wall is made of peptidoglycan.
Why do many species of algae appear green?
The chlorophyll pigment they contain is green.
Which substances are produced during photosynthesis in plants?
carbohydrates oxygen
Photosynthesis Products
simple sugars oxygen
Why are algae considered more valuable for biofuel than plants (such as corn)?
Algae are cheaper to grow than plants.
Cell theory began to develop in 1839, following the research of Matthias Schleiden and Theodor Schwann into plant and animal tissues. Both the botanist Schleiden and the physiologist Schwann noticed that every organism they viewed under a microscope, whether plant or animal, was composed of cells. Their observations that all living species are made up of one or more cells led to the early formation of cell theory. Which tenet of cell theory is described by the paragraph about the historical observations of cells?
All organisms are composed of one or more cells.
_____ can directly use the energy of sunlight to make their own food, and _____ must rely on other organisms to provide the energy they need to survive.
Autotrophs; heterotrophs
You have identified an enzyme that breaks down a storage form of sugar in plants (starch) into simple sugars. How would this enzyme react with a storage form of sugar (glycogen) in humans?
Because enzymes are specific, the plant enzyme's active site would not bind to glycogen as a substrate.
A few unidentified seeds were found in a sealed clay jar during an archaeological dig. Radiocarbon dating showed that the seeds were 725 years old. When the seeds were planted, plants grew from them. Based on cell theory, what statements can confidently be made regarding these unidentified plants and seeds?
Both the seeds and mature plants are composed of cells. The cells in the seeds are still alive, so they produced new plant cells.
If you ingest carbon in the form of sugar, that carbon is released from your body as
CO2
What does the law of conservation of energy state?
Energy can be transformed, but it cannot be either created or destroyed.
How do enzymes catalyze reactions?
Enzymes bind with and change the conformation of substrates.
Which of the statements best describes the overall role of enzymes in metabolism?
Enzymes increase the speed of reactions.
In humans, why is the process of fermentation unable to sustain life?
Fermentation is not efficient at using the energy sources we eat to make ATP.
Generates NDH or FADH2
Glycolysis citrid acid cycle acetyl-CoA production
Anaerobic respiration allows a cell to break down carbohydrates in the absence of oxygen. Identify how NAD+NAD+ is used by animal cells during anaerobic respiration.
Glycolysis requires NAD+NAD+ produced from fermentation to produce ATP.
What would happen if algae, cyanobacteria, and plants were wiped out?
Heterotrophs would not be able to use autotrophs as an energy source.
Many foods—for example, bacon and salt cod—are preserved with high concentrations of salt. How can high concentrations of salt inhibit the growth of bacteria?
High salt is hypertonic and causes the bacteria to shrink because water leaves the bacterial cell.
Glycolysis is a step in the breakdown of glucose. Which statements describe glycolysis?
It is common to aerobic and anaerobic respiration. It produces a net gain of two ATP and two NADH.
Consuming excess amounts of the water-soluble vitamin C can lead to _____ .
It is not possible to consume excess amounts of vitamin C.
Why is cellular respiration referred to as an aerobic process?
It requires oxygen to occur.
Which of the statements regarding potential energy is true?
Potential energy is the energy that an object has based on its position.
Which comparison of prokaryotic and eukaryotic cells is most accurate?
Prokaryotic and eukaryotic cells both contain ribosomes to effectively use their genetic information.
What is the primary role of water in photosynthesis?
The breakdown of water provides electrons and H+ ions for the light reactions.
Which of the following accurately describes why specific material uses a protein to cross the membrane?
The hydrophobic core of a membrane will only allow hydrophobic (i.e., non-polar) substances to cross without a membrane protein.
Which statement describes the function of photosynthetic pigments in leaves?
They absorb light energy to produce high-energy electrons.
Which statement best explains why bacteria are considered living organisms?
They are made of cells.
What is a vitamin?
an organic compound obtained in the diet that is required for normal metabolism
Enzyme
a biological catalyst a protien containing an active site
Select the descriptions that apply to the ribosome.
a cellular structure that is responsible for the synthesis of proteins a cellular structure that is composed of both RNA and protein
Gram-positive and Gram-negative bacteria are most commonly differentiated in the laboratory by whether __________ .
a dye is trapped within the cells during the Gram staining procedure
Which of these describes an anabolic pathway?
a pathway that generates molecules from smaller subunits
active site
a specific enzyme location that binds with the substrate
substrate
a substance that the enzyme acts upon may be phosphate group
In the presence of oxygen, humans use _____ to fuel ATP production from glucose. Glucose is initially formed by plants through _____ .
aerobic respiration; photosynthesis
Corn lacks the essential amino acids isoleucine and lysine. Beans lack the essential amino acids tryptophan and methionine. Soy contains all the essential amino acids. Use this information to complete the following statement: Many traditional diets combine corn (e.g., tortillas) with beans to provide ________.
all the essential amino acids
What subunits are proteins broken down into during digestion?
amino acids
Photosynthesis Reactents
carbon dioxide water light energy
The carbon fixation process of photosynthesis uses ________ energy.
chemical
The energy in a cereal bar is _____ energy. The energy of a cyclist pedaling is _____ energy.
chemical; kinetic
Which organelle do alga need in order to conduct photosynthesis?
chloroplast
Plants synthesize their own food in the form of sugars during the process of photosynthesis. Which of the statements describe photosynthesis?
converts carbon dioxide (CO2)(CO2) to sugars, releasing oxygen (O2) produces sugars for the plant using the energy from sunlight is a cellular process that occurs in the chloroplasts of plant cells
The purpose of aerobic respiration is to , _____ which is used to _____ .
create energy-rich ATP molecules; power functions of the cell
Which eukaryotic cell parts is found in the cytoplasm, transports organelles from one location within the cell to another, and is composed of interconnected protein fibers?
cytoskeleton
Enzymes speed up chemical reactions by ________ .
decreasing the activation energy
Some nutrients are considered essential nutrients because they either cannot be synthesized in the body or cannot be synthesized in sufficient quantities to maintain homeostasis. Essential nutrients must be consumed as part of a healthy and balanced diet.
essential fatty acids vitamins minerals
Our bodies cannot synthesize vitamin C, but they require it in small amounts. Therefore, vitamin C is a(n) ________.
essential micronutrient
Which of the statements are true of endosymbiotic theory?
explains why chloroplasts contain their own genetic information explains the origin of some eukaryotic organelles, such as mitochondria states that an ancestral eukaryotic cell engulfed an aerobic protobacteria
To repair a cell membrane, which macronutrient would supply the needed building blocks?
fats
Which type of organic molecule stores the most energy per gram?
fats
Biological membranes are present in all cells, and they make up the endomembrane system of eukaryotic cells. They have many functions, including acting as barriers that selectively allow the transport of small molecules and ions into and out of the cell or organelle. A biological membrane is a bilayer that contains lipids with
hydrophilic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophobic tail groups pointing inward.
How are biological membranes held together?
hydrophobic interactions
Activation energy is best defined as the energy that
is required to bring the reactant molecules to a transition state.
Fermentation in animals produces _____ , whereas fermentation in brewer's yeast produces _____ .
lactic acid; alcohol
Which organelle would cause the most damage to cytoskeletal fibers in the cytoplasm if its contents were to leak into the cytoplasm?
lysosome
Which component of the peanut butter ready-to-use therapeutic food (RUTF) that Dr. Mark Manary uses provides essential amino acids?
milk powder
Glucose is a product of photosynthesis. Where do the carbon atoms of glucose produced during photosynthesis come from?
molecules in the air
Facilitated diffusion
movemenr of solutions into the cell down their concentration gradient using memebrane protiens
Bulk transport
movement of contents of transport vesicles into the cell by endrocytosis
Active transport
movement of solutes into the cell agaisnt their concentration gradient using membrane protiens
Simple diffusion
movement of solutions into the cell directly through the plasma membrane
Compared to aerobic respiration, fermentation produces _____ ATP.
much less
Which cellular structure is associated with eukaryotic cells but not with prokaryotic cells?
nucleus
Certain nutrients that are important for a healthy and balanced diet are considered essential nutrients. Which of the statements describes essential nutrients for the human body?
nutrients that the body cannot synthesize or does not produce in sufficient quantities
The energy of sunlight exists in the form of _____
photons.
Which of these are components of biological membranes?
proteins lipids
2,4‑dinitrophenol (DNP)(DNP) causes ? to pass directly across the inner mitochondrial membrane instead of returning to the mitochondrial matrix through ? proteins. Because of DNPDNP's effect on the mitochondrion, less energy is captured in the form of ? and more energy is instead wasted as heat.
protons, atp synthase, atp
During fermentation, NADH gives up electrons to regenerate NAD+ by giving electrons to
pyruvate
A macronutrient is a nutrient _______ .
that is required in large amounts
Once excess calories are stored as triglycerides, it is more difficult to release this energy because
the body utilizes food molecules in the bloodstream and stored glycogen first.
What is energy?
the capacity of a system to do work
The cellular respiration process that requires the presence of oxygen is
the electron transport chain.
Choose the best description of kinetic energy.
the energy an object has due to its motion