68 terms

Unit 5 Question Guide

Chapters 5 and 21
the fluid mosaic model describes the plasma membrane as consisting of
phospholipids and proteins
most of the functions of a cell membrane are preformed by
Relaying a message from a membrane receptor to a molecule that preforms a specific function within a cell is called
signal transaction
plasma membranes are selectively permeable, this means that
substances can pass through them
which of the following statements regarding membrane function is false
plasma membrane is control center of cell
small, non-polar, hydrophobic molecules such as fatty acids
easily pass through membranes lilpid bilayer
oxygen crosses through a plasma membrane by
passive transport
diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of
passive transport
osmosis can be defined as
diffusion of water
When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will
exhibit net movement to the side with lower water concentration
In the lab, you use a special balloon that is permeable to water, but not sucrose, to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% waterand is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
water will leave ballon
A cell that never gains nor loses water when it is immersed in a solution is
isotonic to its environment
In a hypotonic solution, an animal cell will
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?
the relative inelasticity and strength of plant cell wall
A plant cell in a hypotonic solution is
is turgid
Facilitated diffusion across a biological membrane requires ___________ and moves substance ____________ its concentration gradient
transport proteins, down
the molecules responsible for membrane transport are
which of the following statements is true among all types of passive diffusion
the concentration gradient is the driving force
which of the following processes can move a solute against its concentration gradient
active transport is driven by concentration gradient
Which of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated in the cell then in the surroundings?
active transport
Which of the following statements regarding active transport id false?
active transport
Certain cells that line the stomach synthesize a digestive enzyme and secret it into the stomach. This enzyme is protein. Which of the following processes could be responsible for its secretion?
The process of a white blood cell engulfing a bacterium is
According to __________, energy cannot be created or destroyed
the first law of thermodynamics
A steer must eat at least 100 pounds of grain to gain less then 10 pounds of muscle tissue. This illustrates
the second law of thermodynamics
What is the basic difference between exergonic and endergonic reactions?
Exergonic reactions release energy; endergonic reactions absorb it
The transfer of a phosphate group to a molecule or compound is called
anything that prevents ATP formation will most likely
result in cell death
when an enzyme catalyzes a reaction
it lowers the activation energy of the reaction
substrates bind to an enzyme's ________ site
the active site of an enzyme is
the region of an enzyme that attatches to a substrate
which of the following statements regarding enzymes is true
enzymes catalyze specific reactions
Heating inactivates enzymes by
changing the enzymes 3 demensions and shapes
humpbuck whales
strain krill with baleene
most animals are
bulk feeders
digestion is the
second step
during which of the following stages of food processing is undigested material removed from the digestive tract
through digestion, polysaccharides are broken into
through digestion nucleic acids are broken down into
an alimentary canal is best defined as
a single tube with specialized regions used to digest food
the main function of an earthworms gizzard is to
mechanically digest food
which of the following choices lits the organs of the bird digestive system in the correct order, from first to last contact with food material
mouth, esophagus, crop, stomach, gizzard, intestine, anus
Which of the following correctly lists
smooth muscle propels food through the alimentary canal by a process called
regulation of the passage of food from the stomach is accomplished by
pyloric sphincter
digestion begins in the
oral cavity
the digestion of carbohydrates begins in the mouth, what is the name given to the starch-digesting enzyme secretes by salivary glands?
the tongue does all of the following except
tastes, shapes, moves towards the pharynx
the epiglottis is a
muscular flap that keeps food from going into the trachea
the Heimlich maneuver is perform to forcibly
dislodge food from the pharynx or trachea
the mucous-producing cells that line the stomach
protect against HCL and pepsin
the stomach mixes food with secretions of the stomach wall to form
heartburn is usually caused by
gastric juice in the esophagus
the function of the pyloric sphincter is to
controls what goes from the stomach to the small intestine
most gastric ulcers are caused by
bacterial infections (helicobacterpylori) in the stomach
in the digestive system, most nutrient absorption occurs in the
small intestine
epithelial cells lining the intestine have surface projections that increase nutrient absorption, these projections are called
bile produced in the liver is stored in the ________ before entering the intestine
gull bladder
which enzyme breaks large polypeptides into smaller polypeptides
which of the following nutrients is digested only after it reaches the small intestine
nutrients absorbed by the intestines move directly to the liver, which
process and store
absorption of water is a major function of the
large intestine
Interestingly, most herbivorous animals do not have the ability to digest cellulose in plants. However, in the absence of this ability, they have evolved a mechanism that allows them to survive despite eating only plant matter, namelt
which of the following digestive system structures is greatly expanded in size in koalas, resulting in a very large surface area for prokaryotes to digest plant matter
large intestine/cecum
all animals must obtain _______ from outside sources
essential nutrients
the rate of energy consumption by the body is called
metabolic rate
a material that must be ingested in preassembles form because the animal cannot synthesize it is
essential amino acids
which of the following vitamins is fat soluble and consequently, can be stored in fat
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