Biology Unit 1

Phospholipids are amphipathic, which means they

Are composed of a hydrophilic portion and a hydrophobic portion.

The _________ of a nucleotide determines whether it is a component of DNA or a component of RNA.

Five-carbon sugar

Your muscle cells need large amounts of ATP to function in the movement of your body. Which of the following organelles would you expect to be especially abundant in muscle cells?

Mitochondria

Which organelle converts the chemical energy stored in food into useable energy for the cell?

Mitochondrion

The diffusion of water across a selectively permeable membrane is called

Osmosis

hyper-

above, excessive

Phago-

eat

chloro-

green

di-

two

Hydro-

water

con-

with, together

Matching

1. central vacuole - water and solute storage 2. nucleus - location of DNA 3. cytoskeleton - internal organization and structural support 4. mitochondrion - cellular respiration 5. ribosomes - protein synthesis 6. rough endoplasmic reticulum - protein synthesis 7. smooth endoplasmic reticulum - lipid synthesis 8. Golgi apparatus - packaging proteins and lipids 9. lysosome - enzymatic breakdown of large molecules 10. plasma membrane - regulate what moves in and out of cell 11. cell wall - structure and support for cell 12. chloroplast - photosynthesis

Which of the following would be the best analogy for the function of the Golgi apparatus?

A worker in a factory who places labels on products and then packs them into a shipping box

chemical reactions in living organisms

All of the above.

The work of Schleiden and Schwann can be summarized by saying that

All plants and animals are made of cells

The monomers of proteins are ________, and these are linked by polar covalent bonds commonly referred to as _________ bonds.

Amino acids, peptide

Which of the following types of organisms are commonly single-celled (unicellular)?

Bacteria, some fungi (yeast), and many protozoans

The versatility of carbon to serve as the backbone for a variety of different molecules is due to

Both a and d

Molecules that contain the element ___________ are considered organic molecules.

Carbon

Living organisms are composed mainly of which atoms?

Carbon, hydrogen, nitrogen, and oxygen

Celli/ cyto-

Cell

The cell takes in food and water and eliminates wastes through the _.

Cell membrane

The thin, flexible barrier around a cell is called the

Cell membrane

Which of the following structures serves as the cell's boundary from its environment?

Cell membrane

Which term refers to cells having different tasks in an organism?

Cell specialization

Which of the following statements most accurately describes a selectively permeable membrane?

Certain solutes move freely across the membrane by simple diffusion while others must be helped across by active or passive transport proteins; some substances are completely excluded from crossing the membrane.

Which organelle would you expect to find only in plant cells?

Chloroplast

Hydrogen bonds differ from covalent bonds in that

Covalent bonds involve sharing of electrons between atoms, but hydrogen bonds are the result of weak attractions between a hydrogen atom of a polar molecule and electronegative atom of another polar molecule.

Which of the following is NOT found in the nucleus?

Cytoplasm

The flexible poles providing structure to a soft-sided tent most closely resemble the

Cytoskeleton in an animal cell or other cell without a cell wall

The ability of an atom to attract electrons in a bond with another atom is termed its

Electronegativity

Using the compound light microscope in the lab room, you observe a wet mount slide preparation. You observe layers of cells that have a definite, rigid, rectangular shape; there appears to be a nucleus in all of the cells and there are many oval-shaped green structures that seem to be moving around inside of the cells in an orderly fashion. What general cell type are you most likely observing?

Eukaryotic and plant

Which of the following is/are part of accepted cell theory?

Every living organism is composed of one or more cells, and all living cells arise from preexisting cells

_________ is a storage polysaccharide commonly found in the cells of animals.

Glycogen

Cells fall into two broad categories, depending on whether they

Have a nucleus

Reactions that involve water in the breaking apart of other molecules are known as _______ reactions.

Hydrolytic

Solutes that easily dissolve in water are said to be

Hydrophilic.

Phospholipids are large organic molecules with a ________, polar phosphate head connected to ________, nonpolar fatty acid tails. How do these molecules arrange themselves to form a mostly impermeable barrier between a liposome and its environment?

Hydrophilic; hydrophobic; They line up hydrophobic tails facing each other at the center line of the membrane with the hydrophilic heads facing outward, away from the center line of the membrane

The smooth endoplasmic reticulum

Is the site where lipids destined for other cellular compartments are manufactured

__________ are molecules that have the same molecular composition but differ in structure and/or bonding association.

Isomers

Which organelle breaks down compounds into small particles that the cell can use?

Lysosome

The boundary that surrounds the contents of the nucleus is the

Nuclear envelope

Which cell structure contains the cell's genetic material and controls many of the cell's activities?

Nucleus

Eukaryotes contain structures that act as if they are specialized organs. These structures are called _.

Organelles

During the process of ________, water diffuses across a semipermeable membrane from an area where water is more concentrated to an area where water is less concentrated (it moves along the water concentration gradient

Osmosis

Osmosis

OsmosisCells naturally, without using energy, respond to changes in water concentration through the process of

The leaves of a plant typically have different tissue layers that function in different ways. The epidermis layer functions like a covering of skin to protect the leaf while vascular bundles carry water and nutrients through the leaf. The palisade mesophyll layer is responsible for most of the photosynthesis that occurs while the spongy mesophyll layer underneath it aids in the exchange of gases (CO2 and O2) and water vapor. In which leaf tissues would you expect to find the highest density of chloroplasts?

Palisade Mesophyll

A white blood cell (WBC) encounters bacteria in a scrape on the knee of a child who has fallen off of his bicycle. The WBC's job is to take the bacteria inside of itself and destroy the bacteria. If the bacteria cannot be moved across the WBC membrane, how will the WBC most likely take it in?

Phagocytosis

An amoeba, a protozoan that moves by pseudopodia, approaches a smaller protozoan and extends its pseudopodia (extensions of cytoplasm in plasma membrane) around the smaller protozoan. Once the amoeba's pseudopodia completely surrounds the other protozoan, the amoeba's plasma membrane pinches off by folding back into the amoeba and creating a vesicle containing the smaller protozoan. This vesicle is now within the amoeba itself and will soon fuse with other vesicles containing digestive enzymes. This is an example of

Phagocytosis

Ribosomes are very small nonmembranous organelles that can either exist freely in the cytoplasm or be embedded in the endoplasmic reticulum of a cell; they are associated with the synthesis of

Proteins

_____________ make(s) up the nucleus of an atom.

Protons and neutrons

Unlike smooth endoplasmic reticulum, rough endoplasmic reticulum has _ attached to it.

Ribosome

Which of the following is an organelle found in the cytoplasm?

Ribosome

Which organelle makes proteins using coded instructions that come from the nucleus?

Ribosome

You are a scientist observing a membrane through which water and some small hydrophobic molecules can freely pass along a concentration gradient from high to low. However, some sugar molecules are too large to pass through the membrane either way without the assistance of passive transport proteins. Additionally, small Na+ ions and some proteins can pass through the membrane against the concentration gradient, but both require the assistance of active transport proteins. What general type of membrane are you observing?

Semipermeable

If a bottle of perfume were spilled in the corner of a large lecture hall, the students sitting near that corner of the room would very quickly smell the perfume. Over time, the students sitting in the far corner of the room would smell the perfume. What phenomenon has occurred to the perfume molecules that have entered the air?

Simple Diffusion

The Golgi apparatus

Sorts proteins and lipids and sends them to their final destination

glyco-

Sugar

The main function of the cell wall is to

Support and protect the cell

Dialysis tubing is a selectively permeable membrane that can be filled with a solution to simulate a cell. A piece of dialysis tubing has been filled with a cloudy white solution of 5 percent starch, 5 percent egg albumin (protein), and 5 percent glucose (a small sugar) dissolved in water to simulate a cell. This cell is weighed and then placed in a beaker of 3 percent iodine dissolved in water. When iodine and starch are mixed together, they form a bluish-black compound that is easily seen. After soaking in the yellow iodine-water solution for one hour, the cell is once again weighed. You also notice that the solution inside of the cell is now a dark blue color while the solution in the beaker is still a light yellow color from the iodine. What do you expect to happen to the weight of the cell over time and what can you deduce from the color change?

The cell should gain weight over time because it is hypertonic to the beaker environment and water will enter the cell through osmosis. The color change indicates that the iodine molecules were small enough to diffuse across the membrane and react with the starch inside the cell. No color change in the beaker tells us that the starch was too large to cross the membrane from the cell and into the beaker.

Compare and contrast the nuclear envelope and the plasma membrane.

The nuclear envelope consists of two concentric phospholipid bilayers while the plasma membrane is only one phospholipid bilayer. Both membranes are selectively permeable and have pores.

You look at the label on a container of shortening and see "hydrogenated vegetable oil." this means that durring processing the number of carbon-carbon double bonds in the oil was decreased. what is the result of decreasing the umber of double bonds?

The oil is now a solid at room temperature

Many important cellular functions in eukaryotic cells occur within membrane-enclosed organelles, such as cellular respiration occurring within the mitochondria. The membranes of the mitochondria provide a place for enzymes needed for cellular respiration to anchor and function. Prokaryotic cells must also carry out respiration but do not have mitochondria. Where is the most likely place that enzymes needed for cellular respiration are anchored and functioning?

The plasma membrane

You buy a bunch of small, round, red radishes at the grocery store; they are on sale because they have been sitting in the produce aisle for a while. When you get home you remove the stems and clean them. With the first bite, you notice their texture is not as crisp and crunchy as you like. Your friend says you should refrigerate them in a bowl of water overnight. The next day the radishes are crisp and crunchy again. What is the most likely explanation of why they became crunchy again after soaking in water?

The radish cells were hypertonic to the water in which they were soaking. So, the water moved by osmosis across the plasma membranes into the radish cells increasing the turgor pressure inside of the cells and making them crunchier.

You are in lab attempting to prepare a slide of cow blood for observation in a wet mount. You place a small drop of the blood on a slide, add a drop of strong saline (salt) solution, and then cover all of it with a coverslip. After returning to your desk, you observe the slide with your microscope and notice that all of the red blood cells (RBCs) do not look like the nice round donut shaped cells in your lab manual. Instead, the RBCs look very shriveled up. Your lab partner has also made a slide, but the RBCs on their slide do look like the ones in the lab manual; your lab partner used a more dilute solution of saline but the same vial of blood. What is the most plausible explanation for the appearance of the blood cells on your slide?

The saline you used was hypertonic to the RBCs; this resulted in water osmosing through the RBC plasma membrane mostly out of the cell.

Examine the figure below. If each sugar molecule represents a percentage point of sugar dissolved in the solution, what change would you expect to see in the solution level over time and why? 10 sugar molecules/less water molecules-5 sugar molecules/more water molecules

The solution level on the left side of the figure would rise while the solution level on the right side of the figure would decrease. This is because the solution on the left side of the figure is hypertonic while the solution on the right side of the figure is hypotonic.

If the concentration of sugar molecules in water on side "A" of a selectively permeable membrane is 5 percent, and the concentration of sugar molecules in water on side "B" of a selectively permeable membrane is 15 percent, which way will the water move and why?

The water will mostly move from side "A" to side "B" because the water concentration is higher on side "A."

Examine the figure below. If each sugar molecule represents a percentage point of sugar dissolved in the solution, what change would you expect to see in the solution level over time and why? 10 sugar molecules/less water molecules-10 sugar molecules/more water molecules

There will be no net movement of water because the solutions are isotonic.

Which of the following statements is true of chloroplasts?

They capture energy from sunlight

Why would hydrophilic substances such as sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids be unable to simply diffuse across a plasma membrane?

They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, they must move across by facilitated diffusion.

During the formation of a peptide linkage, which of the following occurs?

a molecule of water is formed

anti-

against

Diffusion is the movement of particles from

an area of high concentration to an area of low concentration

amphi-

both, on both sides of, around

Quaternary structure is found in proteins

composed of subunits

Lactose, or milk sugar, is composed of one glucose unit and one galactose unit. It can be classified as a

disaccharide

Pino-

drink

iso-

equal, same

lip-

fat

bio-

life

lyso-

loosen, destroy

Meter-

measure

Diffusion occurs because

molecules constantly move and collide with one another

mono-

one

ex-

out, away from

exo-

outside

A protein molecule, transferrin, embedded in the plasma membrane recognizes iron molecules and causes the plasma membrane to fold in around the iron and take it into the cell. This is an example of

receptor-mediated endocytosis

Which of the following is a function of the cell membrane?

regulates which materials enter and leave the cell

homo-

same

micro-

small

Which of the following would be likely to require facilitated diffusion to move across the plasma membrane?

sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids

-ology

study of

-ose

sugar

The major classes of biologically significant large molecules include all of the following except

triglycerides

bi-

two, both

hypo-

under, below

Which of the following would be likely to move through a plasma membrane by simple diffusion?

water (H2O), carbon dioxide (CO2), oxygen (O2)

endo-

within