Biology 171 Midterm 1

The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 g of liquid water by 1°C

1 calorie

Cell theory

1. All living things have at least one cell. 2. A cell is a structural and functional unit of life. 3. Cells come from pre-existing cells (i.e. cells reproduce).

Carbon atom (612C) has how many electrons in its valence shell.

4

Which of these is an example of an anabolic pathway used by cells in their metabolism?

Anabolic pathways build new molecules out of the products of catabolic pathways. An example is the linkage of nucleotides to form a molecule of mRNA.

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.

What is composed of DNA and protein?

Chromatin

Base

a substance that reduces the hydrogen ion concentration of a solution

An ionic bond involves _____.

an attraction between ions of opposite charge

The movement of potassium into an animal cell requires

an energy source such as ATP or a proton gradient

synthesis of sucrose is an example of

anabolic process

The flow of protons into a cell through a transporter protein also moves sucrose inside the cell. Such a transport system is called

antiport and symport

Lipids differ from other large biological molecules in that they

are not truly polymers

Ionic bonds form as a result of

attraction between atoms that have opposite charges ex. sodium and chloride

Which one of the following molecules is most likely to diffuse freely across the lipid bilayer of the plasma membrane without the involvement of a transport protein?

carbon dioxide

Which of these is a polysaccharide?

cellulose (also starch and glycogen)

The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) _____ bond.

covalent

hydrophilic

describes ions or polar molecules that are attracted to and dissolve well in other polar molecules such as water

Geometric isomers are molecules that

differ in the arrangement of their atoms about a double bond

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n)

element

deductive reasoning

general to specific

Ice is lighter and floats in water because it is a crystalline structure in which each water molecule is bonded to a maximum of four other water molecules by which kind of bond?

hydrogen

Which organelle plays a role in intracellular digestion?

lysosomes

In a chemical reaction, a reactant is a

molecule found on the left side of a chemical equation

secondary active transport

movement of material that is due to the electrochemical gradient established by primary active transport

Which transport doesn't require the use of energy?

passive transport

A white blood cell engulfing a bacterium is an example of

phagocytosis

In water, what is the nature of the bond between hydrogen and oxygen?

polar covalent

Although starch and cellulose are polymers of glucose, they are very different chemically. The idea that parts can combine differently to produce different compounds is called

polymer duality

An exergonic (spontaneous) reaction is a chemical reaction that

releases energy when proceeding in the forward direction

The alpha-helix and the beta-pleated sheet are both common polypeptide forms found in which level of protein structure?

secondary

the a helix and b-pleated sheet are part of which protein structure

secondary

The 20 different amino acids found in polypeptides exhibit different chemical and physical properties because of different

side chains (R groups)

vesicle

small, membrane-bound sac that functions in cellular storage and transport

Necleic acids - function

store and transmit hereditary information

The binding of an allosteric inhibitor to an enzyme decreases product formation. This is because

the allosteric inhibitor causes a structural change in the enzyme that deforms the active site.

Which of the following is a major cause of the size limits for certain types of cells?

the need for a surface area of sufficient area to allow the cell's function

Dehydration reactions are used in forming which of the following compounds?

triacylglycerides, polysaccharides, and proteins

Vesicles pinch off the rough endoplasmic reticulum. Where do they go from there?

Golgi apparatus

What is true about the energy released by the hydrolysis of ATP?

It provides energy to coupled reactions.

cytoskeleton

Microfilaments function in cellular movement.

In the five-kingdom system, prokaryotes are placed in the kingdom...

Monera

Mitochondrion (Mitochondria)

One of the main energy transformers of cells

Where are exergonic reactions are coupled to the endergonic reactions?

Catabolic pathways

The shape of hair proteins is maintained by a combination of hydrogen bonds and covalent, disulfide bonds. Heat is sufficient to break the hydrogen bonds, but harsh chemicals are required to break the disulfide bonds. Why is it harder to break the disulfide bonds than the hydrogen bonds?

Covalent bonds are stronger than hydrogen bonds

Which of the following best describes the flow of information in eukaryotic cells?

DNA-->RNA-->Proteins

Why is ATP an important molecule in metabolism?

Energy from ATP hydrolysis can be coupled to drive endergonic reactions

What would happen if even one amino acid is substituted for another in a polypeptide?

The amino acid may not show any significant effect the protein structure and function or it may have a significant effect, as in the case of hemoglobin in individuals with sickle cell trait.

Explain why glucose cannot pass directly through the cell membrane

The plasma membrane is selectively permeable to polar molecules, and a transport protein is required for larger molecules.

integral membrane proteins

They are usually transmembrane proteins.