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in comparing two solutions, the solution with the higher osmolarity
the solution with the most water which will leave the cell to the area with less water outside it
in comparing two solutions, the solution with the lower osmolarity
water moves inside the cell, causing it to swell, because it has less water than outside
A solution with an osmolarity that does not result in water movement across plasma membranes
The process that transports solid objects such as bacteria into the cell
Plasma Membranes are said to be
_____ ion concentrations are high in extracellular fluids, and _____ ion concentrations are high in the cytoplasm.
In a resting transmembrane potential, the inside of the cell is ______, and the cell exterior is _______
- slightly negative
- slightly positive
Our somatic cell nclei contain _____ pairs of chromosomes
THe movement of water across a membrane from an area of low solute concentration to an area of higher solute concentration is known as
The interphase of the cell life cycle is divided into
G0, G1, S, and G2
List the four basic concepts that make up modernday cell theory
- Cells are the building blocks of all plants and animals.
- Cells are produced by the division of preexisting cells.
- Cells are the smallest units that perform all vital physiological functions.
- Each cell maintains homeostasis at the cellular level.
What are four general functions of the plasma membrane?
- Physical Isolation
- Regulation of exchange with the environment
- Structural support
What are the primary functions of membrane proteins?
Membrane proteins function as receptors, channels, carriers, enzymes, anchors, and identifiers
By what three major transport mechanisms do substances get into and out of cells?
- Carrier-mediated transport
- Vesicular transport
List five important factors that influence diffusion rates
- Size of the concentration gradient
- Molecule size
- Electrical forces
What are the four major functions of the endoplasmic reticulum?
- Senthesis of proteins, carbohydrates, and lipids
- Storage of absorbed or synthesized molecules
- Transport of materials
- Detoxification of drugs or toxins
Diffusion is important in body fluids, because it tends to
eliminate local concentration gradients
Microvilli are found in
cells that are actively engaged in absorption
When a cell is placed in a(n) ________ solution, the cell will lose water through osmosis. This process results in the _______ of red blood cells.
Suppose that a DNA segment has the following nucleotide sequence: CTC-ATA-CGA-TTC-AAG-TTA. WHich nucleotide sequences would a complentary mRNA strand have?
How many amino acids are coded in the DNA segment CTC-ATA-CGA-TTC-AAG-TTA?
The sodium-potassium exchange pump....
is composed of a carrier protein located in the plasma membrane
If a cell lacked ribosomes, it would not be able to....
List, in sequence, the phases of the interphase stage of the cell life cycle, and briefly describe what happens in each.
- G0- normal cell functions
- G1- cell growth, duplication of organelles, and protein synthesis
- S- DNA replication and synthesis of histones
- G2- protein synthesis
List the stages of mitosis, and briefly describe the events that occur in each.
- Prophase: chromatin condenses and chromosomes become visible; centrioles migrate to opposite poles of the cell and spinle fibers develop; and the nuclear membrane distintegrates.
- Metaphase: chromatids attach to spindle fibers and line up along the metaphase plate.
- Anaphase: chromatids separate and migrate toward opposite poles of the cell.
- Telophase: the nuclear membrane forms; chromosomes disappear as the chromatin relaxes; and nucleoli appear.
What is Cytokinesis?
the cytoplasmic movement that separates two daughter cells
What is the role of cytokinesis in the cell cycle?
It completes the process of cell division
The transport of a certain molecule exhibits the following characteristics: (1) The molocule moves down its concentration gradient; (2) at concentrations above a given level, the rate of transport does not increase; and (3) cellular energy is not required for transport to occur. WHich transport process is at work?
This process is facilitated diffusion, which requires a carrier molecule but not cellular energy. THe energy for this process is provided by the concentration gradient of the substance being transported. WHen all the carriers are actively involved in transport, the rate of transport reaches a saturation point.
Solutions A and B are separated by a selectively permeable barrier. Over time, the level of fluid on side A increases. Which solution initially had the higher concentration of solute?
Solution A must have initially had more solutes than solution B. As a result, water moved by osmosis across the selectively permeable membrane from side B to side A, increasing the fluid level on side A.
A molecule that blocks the ion channels in intregral protiens in the plasma membrane would interfere with
producing changes in the electrical charges across a plasma membrane
What is the benefit of having some of the cellular organelles enclosed by a membrane similar to the plasma membrane?
The isolation of the internal contents of membrane-bound organelles allows them to manufacture or store secrations, enzymes, or toxins that could adversely affect the cytoplasm in general. Another benefit is the increased efficiency of having specialized enzyme systems concentrated in one place. For example, the concentration of enzymes necessary for energy production in the mitochondrion increases the efficiency of cellular respiration.
The organelle responsible for a variety of functions centering around the synthesis of lipids and carbohydrates is
The smooth endoplasmic reticulum
The construction of a functional polypeptide by using the info in an mRNA strand is