BIO 181 Exam 2

What do you contact-dependent signaling and paracrine signaling have in common?

Cells release a signal that affects neighboring cells

Plant cell walls contain _______.

Cellulose

________ is a polymer of glucose

Cellulose

What structure easily distinguishes a plant cell from an animal or bacterial cell?

Chloroplasts, nucleus, and Golgi apparatus

In Barrow, Alaska, the sun does not set for several months in the summer. Based on what you know about photoperiodism, what type of plant is most likely to flower during the summer in Barrow?

Day-neutral plants

True or false: A dehydration reaction that builds larger molecules from smaller units requires the addition of a water molecule

False

True or false: Osmosis describes the movement of water from an area of HIGH to LOW solute concentration

False

True or false: Saturated fats are composed of fatty acids with several double bonded carbons

False

True or false: Vertical evolution, whereby living organisms evolve from a common ancestor ("tree of life"), is the only mechanism of evolution on Earth.

False

With an atomic mass of 16 and an atomic number of 8, it follows that oxygen

- has eight electrons. - can readily form bonds with 2 other atoms.

If a persons ability to form steroids in their body was destroyed, what function would be affected?

1. Molecular hydrolysis reactions would stop functioning 2. Estrogen would no longer be produced in the body 3. Cholesterol levels would keep increasing causing cell death

How might a plant cell compensate for the excessive membrane fluidity that occurs during prolonged exposures to elevated temperature?

Alter the lipid composition to have longer phospholipid tails and fewer double bonds.

Which of the following are physical stimuli that influence plant responses?

CO2, light, water vapor, gravity

What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+ concentration)?

Calcium movement involves active transport

Eukaryotes differ from prokaryotes, in part because eukaryote cells

Have a membrane-bound nucleus

In the process of biological evolution, new species may evolve through exchange of genes from one species to another is called

Horizontal gene transfer

What type of bonding is likely to occur between two water molecules or strands of DNA?

Hydrogen

The strongest chemical bonds are

covalent bonds

Cyanide binds and impairs one of the molecules involved in the synthesis of ATP. The target organelle for cyanide must be

Mitochondria

Sickle cell anemia is a condition in which red blood cells exhibit a characteristic "sickle" shape. This arises from a mutation or change in one of the amino acids found in hemoglobin. A single amino acid mutation would directly affect a proteins _______ structure

Primary

A cell wall is present in

Prokaryotic and plant cells

Large number of ribosomes are present in Eukaryotic cells that produce

Proteins

A substrate binding to an enzyme is most similar to a signal molecule binding to a

Receptor

The best way to describe cellular membrane is

Semi fluid with lipid rafts

The portion of an amino acid that makes it unique among the 20 different amino acids is its

Side-chain or R group

Diabetics can be given insulin that binds to receptors on cells throughout the body increasing glucose uptake. Insulin is an example of a

Signal

The gonads produce steroids. The specific steroid-producing organelles in gonad cells are

Smooth Endoplasmic Reticulum (Smooth ER)

Roots contain starch-heavy plastids known as:

Statoliths

The subunits (monomers) sometimes build up to form a macromolecule (polymers). Which is NOT a monomer of a polymer

Steroid

The movement of sucrose and H+ into the cell by the same membrane protein reflects the actions of what type of transporter?

Symporter

In some cases, just a few hormone molecules binding to the surface of a cell can trigger a very large response because

The signal is amplified by activation of enzymes that each catalyze multiple reactions

True or false: A community is composed of different populations of animals and plants.

True

True or false: Plant behavior is defined as response to stimuli.

True

True or false: The primary structure of a protein Ultimately determines its three-dimensional structure

True

True or false: Whether a signaling molecule operates locally or over long distances, it must bind to a specific receptor to elicit a cellular response

True

The function of a cell is related to the amount of surface area it has. Is this statement true or false and why?

True. A cell with the same mass can increase surface area with structures like microvilli that enhance absorption functions

The production of second messengers in signal transduction offers at least two advantages, speed and

amplification

Fats and fatty acids...

are insoluble in water

In the periodic table, the value that refers to the number of protons and neutrons is

atomic mass

For water to vaporize

both energy must be supplied and hydrogen bonds broken

The addition of a strong acid like HCl to an aqueous solution would result in

both the release of H+ and a decrease in pH

Which level of organization is common to all life forms?

cell

The organelle responsible for the biosynthesis of proteins that are destined for secretion by the cell is the

endoplasmic reticulum

Following a meal, glucose must move from the gut lumen where there is a high glucose concentration into the intestinal cell where there is a relatively low level of glucose. This movement is called

facilitated diffusion

A significant role played by pH buffers is to

limit major shifts in the amount of H+ and OH- in solution

The process that most involves the selective uptake of a specific cargo molecule into the cell through receptor binding and aggregation is

receptor-mediated endocytosis

Boa constrictor's on an island are an example of a

Population

The organelles most likely to have the ability to divide and reproduce themselves like a cell would be

Both mitochondria and chloroplasts

A cell responds to a signal it sent. This is an example of

Autocrine signaling

A cell secretes a growth factor that binds to receptors on its own membrane preventing it from proliferating. This is an example of:

Autocrine signaling

If the tight junctions in the intestines were disrupted

Bacteria could move from the intestines to the blood stream causing infection

The phenomenon through which populations of organisms change over several generations is termed

Biological evolution

A community of organisms interacting with their physical environment is an

Ecosystem

The nucleus is to eukaryotes as the ________ is to prokaryotes

Nucleoid

An amino acid is to a protein as a _______ is to a nucleic acid

Nucleotide

The LEAST hydrophilic substance is

Oil

A cell secretes a growth factor that binds to receptors on neighboring cells causing them to proliferate. This is an example of:

Paracrine signaling

For heart muscles to beat in a coordinated rhythm ions must move from one cell to the next through _______

gap junctions

During a period of low water availability, the prokaryotic structure that would protect a cell from desiccation (drying out) is the

glycocalyx

Gravitropism is defined as:

growth in response to the force of gravity

How does a macrophage (immune cell) consume a bacteria?

phagocytosis

Gap junctions in animal cells are most similar to ________ in plant cells

plasmodesmata

The nucleus of an atom is composed of

protons and neutrons

Sodium concentrations are higher outside and glucose concentrations are higher inside the cell. Using the same membrane protein for Na+ and glucose transport, what is it called when a Na+ electrochemical gradient is used to drive glucose transport into the cell against its concentration gradient?

secondary active transport

Which membrane component is most important for allowing large, charged molecules to pass through the membrane?

transmembrane proteins