Bio Exam #1 weekly quiz review

A(n) ____________________ is a difference in the concentration of a substance from one place to another.

concentration gradient (also known as chemical gradient)

The bond that forms between amino acids:

connects amino groups and carboxyl groups of adjacent amino acids.

A pair of shared valence electrons is referred to as a(n):

covalent bond

Of the given types of bonds between atoms, which is the strongest in a cellular (aqueous, "watery") environment?

covalent bond

Transmembrane proteins and proteins that will end up in the Golgi apparatus, in the lysosomes, or transported out the cell are built at and transported through the ___________________.

endoplasmic reticulum

Which of the following structures in eukaryotic cells is involved in protein and lipid synthesis (creation)?

endoplasmic reticulum

Which of the examples are cellular life forms: virus, yeast, bacteria, plant, animal?

All are cellular except viruses.

Which of the following would be predicted to have the higher percentage of unsaturated fatty-acid phospholipid tails in their cell membranes?

Arctic (very cold water) fish

"If I grow a plant under green light, it will not grow as well as if I grow it under blue light." This statement is an example of a(n)...

prediction

In scientific inquiry, hypotheses lead most directly to:

predictions

Microtubules, actin microfilaments, and intermediate filaments are made up of _____________________ subunits.

protein

Primary functions of all cytoskeletal fibers are to...

provide structure and help the cell maintain its shape.

____________________ are the "molecular machines" where proteins are built.

ribosomes

In intestinal epithelial cells, a transport protein moves the bulky, polar glucose molecules through the membrane into the cytoplasm, while simultaneously transporting Na+ through the membrane into the cell down its electrochemical gradient. This is an example of...

secondary active transport

Which of the statements is true regarding glycine?

Glycine increases the flexibility of the peptide backbone.

Human ABO blood types are defined by particular sugars that are linked to the proteins and lipids on the surface of red blood cells' plasma membranes. These sugars are added to the lipids and proteins in the _____________________.

Golgi apparatus

Moving a potassium ion (K+) across a cell membrane up its gradient (low-->high) would...

Require a pump and ATP.

Goblet cells are part of the cell layer lining the intestines. They specialize in secreting mucus, which forms a protective layer over the layer of cells. The mucus is made up of glycoproteins (proteins with attached carbohydrates). Which of the following organelles is/are directly involved in the production and secretion of mucus by goblet cells? (Choose all that apply.) Rough ER Smooth ER Golgi Lysosomes Mitochondria

Rough ER & Golgi

Which of the following is an accepted explanation of why a phospholipid bilayer forms in water?

The arrangement minimizes the interactions between water and the hydrophobic tails of the phospholipids.

A bacterial cell, a plant cell, and an animal cell have which structure in common?

a cytoplasm

The metabolic pathway that harvests energy molecules from glucose is highly conserved across many different organisms. From this observation, scientists conclude that the metabolic pathway:

arose early in the evolution of life.

Which of the following is/are TRUE about a falsifiable hypothesis? (Choose all that apply.) A falsifiable hypothesis is testable. A falsifiable hypothesis has been proven wrong. All falsifiable hypotheses can eventually be proven wrong, even if they haven't been proven wrong yet. Some falsifiable hypotheses are correct explanations. Others are incorrect explanations. A falsifiable hypothesis makes predictions that can be compared to experimental results or new observations.

A falsifiable hypothesis is testable. Some falsifiable hypotheses are correct explanations. Others are incorrect explanations. A falsifiable hypothesis makes predictions that can be compared to experimental results or new observations.

Which of the following is/are TRUE about hydrogen bonds?

A hydrogen bond is caused by the attraction of opposite partial charges on two polar molecules (or regions of the same molecule). Hydrogen bonds are much weaker than covalent bonds. Hydrogen bonds between water molecules are responsible for many of water's unique properties. In diagrams, hydrogen bonds are usually shown as dotted lines.

Scientists use which fact as evidence that mitochondria and chloroplasts had prokaryotic origins?

Both contain their own circular DNA.

How is a carrier protein different from a channel protein?

Carrier proteins undergo conformational change so that they are open alternately to one side of the membrane or the other.

Certain neurodegenerative diseases are caused by the failure of cells to break down damaged macromolecules. These molecules build up and damage cells, particularly neurons. Which type of organelle is not functioning normally in these cases?

Lysosomes

Moving O2 across a cell membrane down its gradient (high-->low) would...

Not require a membrane protein or ATP.

Which of the following are structures that are found in prokaryotes AND eukaryotes? (Choose all that apply.) plasma membrane nucleus mitochondria ribosomes DNA

Plasma membrane Ribsomes DNA

Considering the various domains (parts) of a transmembrane protein, which statement would be true?

The domains (parts) of the protein located in the interior of the lipid bilayer (with the fatty-acid tails) would be hydrophobic; the domains (parts) of the protein located on the edge of the bilayer (with the phospholipid heads) or outside of the bilayer would be hydrophilic.

A researcher observes a tissue sample. They conclude that the cells are connected by desmosomes. Which of the following observation(s) could have led to this conclusion? There is no exchange of ions between adjacent cells. The intermediate filaments of the cells' cytoskeletons are connected. The cells are connected at patches or spots.

The intermediate filaments of the cells' cytoskeletons are connected & The cells are connected at patches or spots

Which of the statements is true regarding a basic amino acid?

The positively charged R group of a basic amino acid could bind negatively-charged parts of DNA.

Which of the following ultimately determines a proteins' final 3D shape and function?

The sequence of R groups in the polypeptide chain

What important feature of noncovalent molecular interactions makes them so important to life?

They are weak in a cellular environment, so they can be made, broken, and reformed easily.

Which one of the statements explains a characteristic of both all living organisms and all nonliving material?

They both conform to the basic laws of chemistry and physics.

Suppose that a researcher claimed to have created a genetically modified plant that produces twice as much energy as it harnesses from its environment. How could this be possible?

This is impossible because such a plant would violate the laws of thermodynamics.

True or False? Changing a protein's primary structure (the sequence of amino acids) could change the formation of α helices and β sheets.

True, because the primary structure impacts which secondary structures are likely to form.

"All cheetahs have spots." Is this statement falsifiable? Why or why not?

Yes. If a single cheetah without spots were observed, it would disprove the statement.

Which of the following correctly describes the basic structure of microfilaments?

a double helix of actin proteins

A boy observes a robin outside of his window. He notices the robin repeatedly cocks its head to one side before pecking the ground. The boy suspects that when the robin cocks its head it is actually listening for worms or insects underground. His explanation of the bird's behavior is an example of:

a hypothesis

_______________________ contains enzymes that allow rapid break down of large molecules such as proteins, lipids, and complex carbohydrates when those molecules become damaged or are unneeded by the cell.

a lysosome

Which of the following correctly describes the basic structure of intermediate filaments?

a strong fiber made up of protein subunits that vary by cell type

What is a hypothesis?

a tentative explanation that can be tested by experiments

How are vesicles formed in cells?

a vesicles "pinches off" of an organelle or the cell membrane

Which of the following is/are examples of functions of actin microfilaments in the cell?

associate with the motor protein myosin to transport cellular "cargo" through the cell reinforce the cell's plasma membrane and help organize membrane-associated proteins help maintain the shape of the cell drive some types of cell movement

Neural crest cells are special cells involved in the development of vertebrate embryos. During development, neural crest cells migrate by crawling to various parts of the embryo, where they give rise to many different tissue types. Which of the following is/are necessary for neural crest cell migration? microtubules actin microfilaments myosin

actin microfilaments

The plasma membranes of some plant cells use transport proteins to move protons out of the cell against their concentration gradient. This is an example of:

active transport

Which of the following is the structure that creates a physical connection between the actin microfilaments of cells' cytoskeletons in a sheet of cells?

adherens junction

Which statement is true about the presence or absence of plasma membranes?

all cells have a plasma membrane

Dynamic instability of microtubules (cycles of rapidly falling apart then slowly building back up)

allows microtubules to perform their functions.

Some diseases result from defective transport across the membrane. For example, cystic fibrosis results when a chloride ion transporter does not function. What is affected when this transporter does not function?

both the chloride concentration gradient and the electrical gradient of the cell

A protein molecule is synthesized (produced)...

by a free-floating ribosome in the cytosol or a membrane-bound ribosome on the rough endoplasmic reticulum.

A function of kinesin and dynein motor proteins is to use the energy of ATP to:

carry vesicles containing "cargo" (such as proteins or other molecules) along microtubules to transport them through the cell.

Proteins that do not refold properly after being heated generally require the assistance of which type of molecules in cells?

chaperones

What would be found in the cells of a blade of grass but not in the cells of an insect feeding on that grass?

chloroplasts

__________________are the organelles in plant cells that carry out photosynthesis.

chloroplasts

Which structures are linked to intermediate filaments of the cytoskeleton to create a strong physical connection?

desmosomes

Which are examples of a motor protein? Select all that apply.

dynein, myosin, and kinesin

A(n) __________________ is a difference in the charge from one place to another.

electric gradient

The protein-assisted movement of a polar molecule across the membrane that does not require ATP or the input of energy occurs through:

facilitated diffusion

Purified phospholipids mixed in water will only form membranes if the appropriate enzyme is present.

false

T or F Given that plant cells have chloroplasts, mitochondria are actually unnecessary in plant cells.

false

Theories typically rely on a single hypothesis tested several times; theories do not take into consideration multiple hypotheses.

false

True or False? Different organelles work alone--they don't interact physically or functionally. That is, they do not touch, and each performs a separate "job" that does not involve other organelles.

false

True or False? Signal sequences are carbohydrate tags added to a protein to direct it to its final location.

false

Which of the following types of cell junctions allow materials to pass directly from the interior of one animal cell into another?

gap junctions

All cells have:

genetic information

Two major types of protein secondary structures are referred to as:

helix and sheet

Which of the following is/are examples of functions of microtubules in the cell?

help maintain a cell's shape and internal structure help cells resist pressure/withstand compression guide arrangement of organelles within the cell act as tracks for transport of cargo-carrying vesicles within the cell attach to and help position chromosomes during cell division

Secondary structure is characterized by which type of interactions?

hydrogen bonding within the peptide backbone

Which of the following is a tentative explanation for a phenomenon (something that is observed to happen)?

hypothesis

If a mutation that causes a change in a human cytoskeletal protein only impacts certain tissues and leaves others completely unaffected, what type of cytoskeletal filament(s) is/are most likely affected? microtubules actin microfilaments intermediate filaments

intermediate filaments

Scientists refer to the idea of biological evolution via natural selection as a "theory" because...

it is an idea that explains a lot and has a lot of evidence supporting it.

In which eukaryotic organelle are various macromolecules broken down and destroyed?

lysosomes

The experiment described in Figure 5.8, in which researchers (1) labeled membrane proteins with a fluorescent label, (2) photobleached an area of the membrane, and (3) observed that fluorescence gradually returned to the bleached area, demonstrated that...

membrane proteins move in the plane (within the surface of) the membrane.

Some cytoskeletal elements are more permanent than others. Which components of the cytoskeleton are dynamic structures? Select all that apply.

microfilaments and microtubules

Disruption of which of the following would prevent an animal cell from undergoing cell division normally? microtubules actin microfilaments intermediate filaments

microtubules & action microfilaments

Heart cells consume a vast amount of chemical energy to keep the heart continuously pumping. Therefore, it is not surprising that a heart cell has more _______________ than any other cell type in your body.

mitochondria

Individuals with a condition known as exercise intolerance lack sufficient ATP and suffer extreme fatigue from minimal exertion. Defects in which structures are most likely responsible for this condition?

mitochondria

The interior of a lysosome is __________, which is optimal for the function of the enzymes inside of the lysosome.

more acidic than the cytosol (lower pH)

In eukaryotic cells, RNA is synthesized (built) in which organelle?

nucleus

An ionic bond forms when...

one atom "steals" one or more electrons from another atom and the resulting opposite charges on the two atoms attract them to each other.

Some plant cells create a high concentration of protons outside the cell to move solutes, such as sucrose, across the plasma membrane into the cell where the sucrose concentration is already relatively high. This type of transport is an example of:

secondary active transport.

describe the function of the plasma membrane?

separates the internal cell contents from the surrounding environment and maintains homeostasis within the cell

Phospholipids (which are the primary component of cell membranes) are made in the __________________________.

smooth ER

The Golgi apparatus has three primary roles. They are (choose 3):

synthesizing (making) most of the cell's carbohydrates, acting as a "sorting station" as lipids and proteins are moved to their final destinations, and modifying proteins and lipids that are transported to the Golgi from the endoplasmic reticulum

The fully folded structure of a functional protein composed of a single polypeptide chain is referred to as:

tertiary

What accounts for the ability of vesicles to fuse with different membrane compartments in the cell?

the fluid nature of the phospholipid bilayer

In which eukaryotic organelle are some macromolecules broken down to obtain useful energy for the cell in the form of ATP?

the mitochondria

The passage of molecules and ions across the cell layer lining the lungs is tightly controlled (see the figure for clarification). This helps maintain the environment needed for the lungs to function. Which of the following types of cell junctions is necessary for this control?

tight junctions

Which of the following types of cell junction creates a tight seal between cells?

tight junctions

True or False? A potassium ion pump would include a signal-anchor sequence.

true

True or False? A protein with a signal-anchor sequence will be synthesized a ribosome bound to the endoplasmic reticulum.

true

True or False? A signal-anchor sequence allows a protein to be inserted into the membrane of the rough endoplasmic reticulum as the protein is being synthesized (produced).

true

True or False? Molecules such as mRNA and proteins move into and out of a eukaryotic cell's nucleus through nuclear pores.

true

A polar covalent bond is due to:

unequal sharing of electrons in a covalent bond.

Which of the following are properties of water than result from hydrogen bonding between water molecules?

water sticks to other water water has high surface tension (the surface of water is relatively difficult to break through) ice is less dense than water water is an exceptionally good solvent for polar compounds and salts it takes a lot of heat to increase the temperature of water

A transmembrane protein (for example, a membrane transport protein)...

will be synthesized by a ribosome bound to the rough endoplasmic reticulum.

A protein that will eventually be secreted from the cell...

will have a signal sequence directing it to the rough endoplasmic reticulum (while the protein is still being synthesized/produced).