week 3
in order for diffusion to occur, there must be a
concentration gradient
which factor determines the direction of diffusion in all cases
concentration gradient
A __________ gradient drives the movement of solutes for diffusion, whereas a __________ gradient drives the movement of fluid for filtration.
concentration; pressure
Air is a solution of gases. It is composed of 1% water vapor, 0.04% carbon dioxide, 21% oxygen, and 78% nitrogen. Which of the gases is the solvent?
nitrogen
diffusion is a passive process because
no cellular energy is use for this mechanism
A bond in which electrons are shared equally
nonpolar covalent bond
composed of both protein and RNA
nucleolus
contains the cells genetic material (DNA)
nucleus
which one of the following component of a human cheek cell will be stained most intensely with methylene
nucleus
what factors are responsible for the tonicity o a solution
number and type of solutes present and membrane permeability
necessary for survival of the body
nutrients, oxygen, water, atmospheric pressure
reactions in the body are
often reversible and rarely proceed to completion
which of the following solutions contains the smallest concentration of water molecules
1 liter of 20% salt solution
plasma membrane structure
1. It is the boundary, which separates the living cell from their non-living surroundings. It is the phospholipids bilayer. 2. Plasma membrane is an amphipathic, which contains both hydrophilic heads and hydrophobic tails. 3. It is a fluid mosaic of lipids, proteins and carbohydrate. 4. It is lipid bilayer, which contains -two layers of phospholipids, phosphate head is polar (water loving), fatty acid tails non-polar (water fearing) and the proteins embedded in membrane.
plasma membrane function
1. It separates the contents of the cell from its outside environment and it regulates what enters and exits the cell. 2. plays a vital role in protecting the integrity of the interior of the cell by allowing only selected substances into the cell and keeping other substances out. 3. It also serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others. Thus the cell membrane supports the cell and helps in maintaining the shape of the cell. 4. The cell membrane is primarily composed of proteins and lipids. While lipids help to give membranes their flexibility and proteins monitor and maintain the cell's chemical climate and assist in the transfer of molecules across the membrane. 5. The lipid bilayer is semi-permeable, which allows only selected molecules to diffuse across the membrane.
in order of which diffusion occurs most easily
1. air 2. liquid 3. semi solid
plasma membrane characteristics
1. the plasma membrane (cell membrane) is made of two layers of phospholipids. The plasma membrane has many proteins embedded in it. 2. The plasma membrane regulates the entry and exit of the cell. Many molecules cross the cell membrane by diffusion and osmosis. 3. The fundamental structure of the membrane is phospho lipid bilayer and it forms a stable barrier between two aqueous compartments. 4. The proteins present in the plasma membrane, act as pumps, channels, receptors, enzymes or structural components.
components of the plasma membrane
1.Proteins like glycoprotein, which are used for cell recognition and act as receptors and antigens. 2. Proteins like glycolipids are attached to phospholipids along with the sugar chains. 3. Lipids with short chain of carbohydrates are attached on the extracellular side of the membrane. 4. Phospholipid Bilayer - which are made up of phosphates and lipids. They create a partially permeable membrane, which allows only certain substances to diffuse through the membrane. 5. Cholesterol - it maintains the fluidity of cell surface membrane.
Microfilaments
Actin; involved in cell motility, found in muscle cells and amoeba; in plants, they promote cytoplasmic streaming small rodlike structure, about 4-7 nanometers in diameter, present in numbers in the cytoplasm of many eukaryotic cells.
To test the permeability of dialysis tubing to glucose, which chemical would you use as an indicator of the presence of glucose?
Benedicts solution
Diffusion differs from active transport in which of the following ways?
Diffusion occurs due to random kinetic energy in the molecules
In osmosis, water will move in what direction
From the area with lower solute concentration (higher water concentration) to high solute concentration (lower water concentration)
protein synthesis
Forming proteins based on information in DNA and carried out by RNA. it is a sequences need to be "decoded" and then translated in order to form the protein.
Stack of membranes that packages, sorts, and distributes cellular compounds
Golgi apparatus
a stack of flattened membranes that are the site where proteins from the ER are modified, packaged, and sorted for delivery to other organelles or to the plasma membrane of the cell
Golgi apparatus
Which property of water is demonstrated when we sweat?
Heat of vaporization
what happens when iodine is added to a solution containing starch
Iodine changes from light yellow to blue black in color
During homeostasis, the body
Maintains dynamic equilibrium within a narrow range
molecular motion
Molecules move in random directions
What is the difference between passive transport and active transport?
Passive transport (diffusion) moves ions from high concentration to low, using no metabolic energy. Active transport moves ions from low concentration to high, using metabolic energy in the form of ATP. Active transport uses an ion pump (sodium/potassium pump) to move 3 sodium ions out of the cell and 2 potassium ions in to the cell through the energy of 1 ATP molecule.
plasma membrane
Plasma membrane can be defined as a biological membrane or an outer membrane of a cell, which is composed of two layers of phospholipids and embedded with proteins. It is a thin semi permeable membrane layer, which surrounds the cytoplasm and other constituents of the cell.
Translation (protein synthesis)
Process by which mRNA is decoded and a protein is produced. Translation is the second stage of protein synthesis where the mRNA is translated into a protein. This involves another RNA molecule, transfer RNA (tRNA). tRNA matches three nucleotides at a time from the mRNA. These 3-nucleotide sequence combinations are called codons. There are 64 possible combinations; for example
Passive Transport (Diffusion)
Requires no energy to move molecules from high to low concentration
Which of the following is true of passive transport mechanisms like diffusion?
They transport substances from areas of high to low concentrations
Chemotherapy treatments are given to cancer patients in an attempt to halt or slow the growth of a tumor, which is composed of rapidly dividing cells. Certain chemotherapy drugs exert their actions by interfering with mitosis. For example, some drugs act to prevent microtubules from shortening. Microtubules are protein filaments that attach to chromosomes and move them during mitosis. Based on this role of microtubules, with which stage of mitosis would these drugs most likely interfere?
anaphase
which of the following is an example of molecular movement by diffusion
a bottle of perfume is opened at the front of the classroom and 10 minutes later you can smell it on the back of the room
chemical reactions progress at
a faster rate when the reacting particles are present in higher numbers
why does blood become transparent in hypotonic solution
a hypotonic solution causes cells to burst, and this makes the solute transparent
a solution is a mixture of
a solute dissolved in another substance known as a solvent
Some membrane transport mechanisms utilized by cells are active, while others are passive. Which of the following are ways in which active and passive mechanisms differ?
active mechanisms can be used to transport substances from low concentration to high Passive mechanisms like diffusion can only transport from high concentration to low Active mechanisms require the use of cellular energy in the form of ATP
Electrically charged particle due to gaining of an electron
anjon
intermediate filaments
are proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments. they extend throughout the cell to provide support and strength
How is genetic information coded in DNA
based on the sequence of nucleotides
When preparing a wet mount of human cheek cells, methylene blue is what kind of dye
basophilic
why does blood become transparent in the hypotonic solution
because the fragments from burst cells are small and don't stop the light
Identify blood in hypotonic solution
blood cells lyse or burst in a lyse or burst in a hypotonic solution because there isa net movement of water into cells. you do not see intact cells
what happens in redox reactions
both hydrolysis (decomposition) and electron exchange occur
Delivers oxygen and nutrients to the tissues, distributes heat
cardiovascular system
Electrically charged particle due to loss of an electron
cation
what did I see in the microscope slide with a elodea leaf in a hypertonic solution
cells that have shrunk because of osmosis, an elodea leaf in a hypertonic solution
paired organelles composed of microtubules that are used to organize the mitotic spindles that attach to chromosomes during mitosis
centeroles
what did I see in the microscope slide with an elodea leaf in a hypotonic solution
chloroplast close to the cell walls, cells with the central vacuole full of water, an elodea leaf in a hypotonic solution
Genetic material within the nucleus; consists of DNA and associated proteins in an "uncoiled" form
chromatin (Chromatin is uncoiled DNA)
Prophase
chromatin coils into chromosomes, which become visible when viewed with a light microscope
anaphase
chromosomes are being pulled toward the opposite poles of the cell
Telophase
chromosomes are located at opposite ends of the cell; a cleavage furrow may be visible
metaphase
chromosomes lineup at the center of the cell along the equatorial plate
based on your experiments, you can say the the ammonium chloride cloud forms
closer to the HCI source
includes organelles and cytosol; cytosol contains enzymes that mediated many reactions such as glycolysis and fermentation
cytoplasm
composed of protein filaments called microtubules, intermediate filaments, and micro filaments; provides structural support for the cell
cytoskeleton
The term ____________ refers to fluid in the cell that contains enzymes mediating certain reactions, such as glycolysis and fermentation, but it does not refer to the organelles.
cytosol
an increase in viscosity of the solvent will
decrease the diffusion rate
Which of the following factors increase the rate of diffusion of a substance?
decreased viscosity of the solvent
osmosis is classified as a special case of which form of membrane transport
diffusion
in general, what is the effect of the type of medium on diffusion rate
diffusion rate is greater in fluid media than solid
If experiments were allowed to continue for an indefinite period of time, what would eventually happen?
dynamic equilibrium when all the solutes are even distributes
Term for atoms having a high affinity for electrons
electronegativity
Smallest particle of a compound that still retains its properties
element
Controls the body with chemical molecules called hormones
endocrine system
maze that plays a role in the synthesis of steroid-based hormones and proteins
endoplasmic reticulum
Methylene blue is most attracted to acid-loving, ___________________ (basophilic/eosinophilic) components of the cell.
eosinophilic
net diffusion will always occur
from high to low concentration
whether in a gas, a liquid, or semi solid, diffusion always occurs
from high to low solute concentration
What is a vertical section through the body, dividing it into anterior and posterior regions called?
frontal
solute molecule can move most freely through
gas
which medium are solvent molecule most widely spaced
gas
which solute in your experiment diffused from the dialysis tubing bag into the beaker
glucose
chemical reactions proceed more quickly at
higher temperatures
Microtubules function
hollow tubes of protein that can act as tracks along which organelles move Support cell; hold organelles in place; maintain cell shape and rigidity; direct organelle movement within cell and cell motility as cilia and flagella; move chromosomes at cell division
what is important to know about diffusion in different media
how the rate of diffusion depends on the density of the medium how diffusion rate depends on molecular speed
Which bonds often bind different parts of a molecule into a specific three-dimensional shape?
hydrogen
A type of weak bond based on charge attraction, important in tying different parts of the same molecule together into a three-dimensional structure
hydrogen bond
Which one of the following systems responds fastest to environmental stimuli?
nervous
a cell is placed in a 15% solute and the cell shrinks. What is the tonicity of this solution
hypertonic
a solution that has a higher osmotic pressure than intracellular fluid
hypertonic
a solution that has a lower osmotic pressure than intracellular fluid
hypotonic
Protects underlying organs from environmental damage and synthesizes vitamin D
integumentary system
the stage of the cell cycle when cells are to undergoing mitosis is
interphase and individual chromosomes are not visible within the nucleus of the cell
when a red blood cell is place in a hypertonic solution, which will occur
intracellular volume will increase; lysis
Which solute could diffuse from the beaker into the bag?
iodine
what happens when iodine is added to a solution containing starch
iodine changes from light yellow to blue black in color
a bond in which electrons are completely lost or gained by the atoms involved
ionic bond
A patient enters the emergency department with considerable blood loss from blunt force trauma. The physician attending to the patient needs to increase the volume of the patient's bodily fluids so the patient's blood pressure and systemic perfusion of tissues can be maintained. The physician quickly administers an intravenous solution of NaCl. To avoid causing more harm to the patient, the tonicity of the intravenous solution should be ___
isotonic
a solution that has the same osmotic pressure as intracellular fluid
isotonic
which types of solutions should be used when preparing a wet mount
isotonic
Atoms of the same element with differing numbers of neutrons
isotopes
the average diffusion rate in a semi-solid like agar is around 50mm/h over the first 15 minutes. what can you say about the diffusion rate in a liquid based on your results
it is greater than the diffusion speed in a semi solid
Oxygen diffuses from the blood to the tissues of the body. What is a true statement about the movement of oxygen?
it moves from an area of high concentration in the blood to an area of low concentration in the tissues
While on vacation you run out of contact lens solution. In an attempt to improvise, you use tap water to hydrate the contact lenses. Immediately after you put the lenses in your eye, you feel intense pain. Why did the tap water cause such pain?
it was a hypotonic solution that altered the hydration of the cornea
in which quadrant of the abdominopelvic cavity is the stomach located
left upper quadrant
Removes and filters excess fluid from tissues, returns leaked fluid to blood
lymphatic system
membrane enclosed sacs that contain digestive enzymes and function in the breakdown of intracellular molecules
lysomes
Organelle with digestive enzymes and high acid content to break down particles
lysosomes
Tonicity of a solution
measure of the ability of a solution to cause change in cell shape or tone by promoting osmotic flow of water
cytoskeleton structure
microfilaments and microtubules
Three separate types of protein molecules form the cytoskeleton
microfilaments, intermediate filaments, and microtubules
Organelle largely responsible for cellular respiration and ATP synthesis
mitochondria
often referred to as the "powerhouse" of the cell, these organelles are the site of cellular respiration
mitochondria
where do oxidative phosphorylation and aerobic ATP synthesis occur
mitochondria
Cancerous cells (tumors) involve a malfunction in which cellular process
mitosis
what factor determines which solutes can pass across the membrane of dialysis tubing
molecular size
Which of the following properties that influence the rate of diffusion is studied when measuring the diffusion distance of both methylene blue and potassium permanganate in agar?
molecular weight of the substance
which factors does molecular speed depend on
molecular weight, temperature, type of medium
which of the following explains the mechanism of diffusion
molecules spread randomly from areas of higher concentration to areas of lower concentration
In the region of high concentration of each substance, why is there a net movement of molecules outward?
more molecules collide within the region of high concentration
Directly causes mechanical motion, produces heat
muscular system
Feedback mechanisms regulate biological systems
negative and positive feedback Negative feedback mechanisms work to prevent sudden severe changes within the body
the movement of water across a semipermeable membrane
osmosis
a cel contains intracellular fluid that is approximately 0.9% solutes. If a cell is placed in a 5% salt solution, in which direction will there be a net movement of water
out of the cell
Mitosis
part of eukaryotic cell division during which the cell nucleus divides
membrane enclosed sacs that contain oxidative enzymes (eg catalase)
peroxisomes
functions of plasma membrane
physical barrier, selective permeability, electrochemical gradients, communication it is composed of a phospholipid bilayer it encloses the cell contents in such a way that water in the body is divided into separate compartments it acts as a site of cell to cell interaction and recognition it is selectively permeable but permits water and gasses to cross
provides a selectively permeable barrier between the intracellular and extracellular environment of the cell
plasma membrane
A bond in which electrons are shared unequally
polar covalent bond
phases of mitosis
prophase, metaphase, anaphase, telophase
cytoskeleton function
protein filaments that anchor to the cell membrane to allow for cell structure, movement, etc.
Neurons contain large amounts of rough endoplasmic reticulum. Neurons are cells that transport numerous ions into and out of the cell. They need to synthesize many ion channels and pumps to insert into their plasma membranes. Knowing this, what function of rough endoplasmic reticulum makes it so important to neurons?
protein synthesis
What are the biological molecules responsible for doing work in cells and acting as enzymes?
proteins
Term for an unstable atom that decays, or splits apart, over short or long periods of time
radioactive
What drives diffusion?
random movement of molecules
Polymers, such as carbohydrates and proteins, are built up from their monomer building blocks by:
removal of a water molecule between each two units
Certain cells within the pancreas function in the synthesis and secretion of the hormone insulin, which is a protein. Based on this function, what organelle(s) do you predict these cells would contain large numbers of?
ribosomes
The actual site of protein synthesis
ribosomes
sites of protein synthesis; may be bound to ER ("bound") or found within the cytoplasm ("free")
ribosomes
synthesizes new proteins destined for the plasma membrane, for lysosomes, or for secretion from the cell
rough endoplasmic reticulum (RER)
in what medium does molecular movement occur
semi solid, liquid and gas
in which substance can diffusion occur
semi solid, liquid, air
Provides support and levers for muscles to pull
skeletal system
one major function of liver cells (hepatocytes) is to detoxify alcohol. Based on this function, what organelle do you predict hepatocytes would contain a large number of?
smooth ER
Where is the site of lipid synthesis and detoxification of drugs and alcohol?
smooth endoplasm reticulum
substances that dissolve in a solution
solute
suppose you have a solute molecules at a very high concentration at a specific location in a solvent. all molecules move around randomly. what will happen over time
solute molecules will spread out evenly
solution into which another substance dissolves
solvent
dialysis tubing is selectively permeable. This means that
some solute will pass thought and other will not
Which solute was too large to diffuse through the membrane?
starch
what solute is too large to diffuse through a dialysis tubing membrane
starch
a red blood cell placed in pure water would
swell and burst (lyse)
Transcription (protein synthesis)
synthesis of an RNA molecule from a DNA template. s the first stage of protein synthesis. It is the process of reading the DNA, this is carried out by enzymes within the nucleus. The "transcript" from this process is another chemical molecule called messenger ribonucleic acid or mRNA. RNA is very similar to DNA in structure except it has only one strand compared to DNA which is double-stranded.
Which of the following directly affect the rate of diffusion in an aqueous solution?
temperature of the solvent molecular weight of the solute viscosity of the solvent
Tay Sachs is caused by
the absence of a vital enzyme called hexosaminidase-A (Hex-A) in the vesicular organelle
how does a concentration gradient affect diffusion rate
the bigger the gradient the faster the rate
what determines the direction of diffusion
the concentration gradient-high concentration to low
Suppose solute molecules are highly concentrated and that diffusion happens fast. What will the distribution of solute be like after a long time?
the concentration of solute will be equal everywhere
a concentration gradient exists in a solution when
the concentration within the solution is not the same everywhere
the greater the concentration gradient
the faster the diffusion rate
how does the speed of diffusion depend on the speed of the molecules
the faster the molecules move, the greater the diffusion speed
how is the concentration gradient of water related to osmotic pressure
the greater the concentration gradient of water across a membrane, the greater the osmotic pressure
the ammonium chloride cloud forms closest to the substance with the higher molecular weight because
the higher molecular weight substance diffuses more slowly than the lighter one
what conditions must be present before a solute can diffuse across a membrane
the membrane must be permeable to the solute there must be unequal concentration on either side of the membrane
what explains that the ammonium chloride cloud forms closer to the HCI source?
the molecular weight of HCI is greater than the molecular weight of ammonia- and diffusion speed decreases as molecular weight increases
active transport
the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.
Identify blood in an isotonic solution
the normal shape and volume of cells is maintained in isotonic solution because there is no net movement of water in or out.
based on your data, which statement is correct
the stable level increases with increased concentration of solute
in an experimental set up, starch is placed in dialysis tubing and suspended in water. When Iodine is added to the water, over time the starch solution in the bag turns black, while the color of the water remains the color of diluted iodine. Which of the following most likely occurred?
the starch stayed in the bag and the iodine leaked into the bag and reacted with it, turning the solution black
Iodine is added to an unknown solution, and it turns from a light yellow color to a blue black color. What does this indicate about eh solution to which the iodine was added
the unknown solution contains starch
a solution with a high solute concentration contains less water than a solution with a low solute concentration. keeping this in mind, which of the following explains the nature of osmosis (a solute is a substance that is dissolved in a solution)
there is a greater chance that more molecules will move across the membrane from the side with lower solute concentration to the side with higher solute concentration
what happens during diffusion
there is a net movement of molecules from areas of high concentration to areas of low concentration
The color spreads outward because..
there is net movement of each substance form an area of high concentration to low concentration
Which of the following will occur if the concentration of membrane-impermeable solutes in the intracellular fluid of a cell is higher than the concentration of such solutes in the extracellular fluid?
there will be a net movement of solutes into the cell there will be a net movement of solutes OUT OF the cell and water INTO the cell there will be a net movement of solutes INTO the cell and water OUT OF the cell
interphase
uncoiled chromatin exists within the nucleus of the cell; chromosomes are not visible when viewed with a light microscope
enzymes increase the rate of chemical reactions, sometimes while
undergoing reversible changes in shape
Membrane-bound sacs that are used to transport and organize compounds in the cell
vesicles
Which of the following properties that influence the rate of diffusion is studied when measuring the diffusion distance of potassium permanganate in both water and agar?
viscosity of the solvent
osmosis is a special case of diffusion because it only involves the movement of what substance
water
what is the solvent in biological solutions such as cytoplasm and blood
water
in the lab you are observing a wet mount of erythrocytes. the field of view is very crowded and it is hard to see individual cells. in an attempt to see them better, you make a second preparation by diluting the original sample. when you try to find the cells there are none. Which of the following is a plausible explanation for what went wrong
you accidentally diluted the sample with distilled water and caused the cells to lyse
