biology test 1

This is a molecule with a large molecular mass. Many examples come from biology and in particular biochemistry.

Macromolecule

This is a macromolecule that holds cell information in a coded form. Made of sugar, phosphate and nitrogen-containing bases.

Nucleic Acid

A macromolecule that contains carbon, hydrogen, oxygen, and nitrogen, which is used by the body for growth and repair.

Protein

Protein

Some are stringy and fibrous and provide support (i.e., collagen and keratin) Help speed up cellular reactions

Which of these organic molecules functions to help speed up biological chemical reactions?

proteins

A macromolecule made up of mainly carbon and hydrogen atoms that is primarily used for energy storage and in cell membranes.

Lipid

This is the main energy storage and transfer molecule in the cell.

ATP

This is a compound made up of carbon, hydrogen, and oxygen atoms; it is used by cells to store and release energy. Sugars are made by chloroplasts through photosynthesis and consumed by mitochondria through cell respiration.

CARB

Lipid

Can provide insulation

This holds an organisms hereditary information.

DNA

Which statement BEST explains why the specific heat of water is higher than the specific heat of most other substances?

Due to the ionic bonding in liquid water, it takes more heat energy to reach boiling.

A person starts to eat a hamburger. As she takes a bite and chews, an enzyme called salivary lipase helps to begin the process of fat digestion. Which of these is the BEST description of the role of enzymes in digestion?

Enzymes are cells that secrete saliva and other necessary substances needed for digestion.

Enzymes, such as the one shown in the picture, work by fitting onto the substrate molecule like a lock-and-key action. Which statement is true, with regard to the enzyme and the substrate?

The enzyme weakens chemical bonds in the substrate and catalyzes a change into the product. The enzyme itself remains unchanged.

This is the repeating structural unit that forms RNA and DNA.

This is the repeating structural unit that forms RNA and DNA.

Carbohydrate

Used as main source of energy for a cell

Water is unusual because it expands as it freezes. Very few substances have this property. The reason liquid water is more dense then ice can be best explained by?

Water is polar and the positive and negative ends of the molecule attract each other.

Which compound is a reusable, complex protein that speeds up chemical reactions?

an enzyme

Catalysts increase the rate of a reaction by

lowering the activation energy of a reaction.

The students in Ms. Hill's science class were investigating the properties of water. They placed a piece of celery in a beaker of blue water. The next day, the celery was no longer green, but blue, all the way up to the leaves. What property of water BEST explains why the blue water moved up the celery stalk?

capillary action

The carbohydrates seen here contain three common elements. They are

carbon, hydrogen, and oxygen.

Surface tension is a property of water that is the result of polar water molecules sticking together or water's property of

cohesion

Water molecules are ____________ due to _________bonding. This property helps water molecules to stick to each other and allows for the movement of water from plant roots up to plant leaves.

cohesive; hydrogen

nucleic acid

contains genetic information

The water cycle consists of some water evaporating from the surfaces of bodies of water and going into the air. As result of air temperatures, water vapor eventually condenses and falls as rain. The rain nurtures life and the environment and eventually makes its way back into water where the cycle is repeated. Water has an unusually low vapor pressure and does not rapidly evaporate because of its

hydrogen bonding.

Water is called the universal solvent because

it dissolves many substances

One of the many unique properties of water is that its solid form (ice) is less dense than its liquid form. Most substances become more dense when in solid form, because their molecules are more tightly compact. Why is this property of water so important to life on Earth?

surface water freezes and insulates the water below for marine life

Living matter is at least sixty percent water. It makes sense, then, that cell membranes are made of phospholipids because

the lipids form an insoluble barrier.