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