Cell Bio Test #1

Which of the elements in the periodic table are the most important to biomolecules:

Carbon, hydrogen, nitrogen, oxygen

Covalent bonds:

Carbon-carbon bonds are non-polar - electrons are shared equally by the two participating atoms ; Oxygen-hydrogen covalent bonds are polar - oxygen has more electronegativity than hydrogen, and the electrons on the O-H covalent bond are drawn preferentially towards oxygen

What is the chemical reaction mechanism by which cells make polymers from monomers:

Dehydration reaction

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified:

As a disaccharide

The immediate phosphorylation of glucose following its transport into the cell converts the glucose into a form for use in cellular respiration. True or false:

True

Starch is broken down into glucose monomers by which of the following mechanisms:

Hydrolysis

Respiration oxidizes glucose to produce _, the primary energy currency of the cell:

ATP

Which of the following types of molecules are the major structural components of the cell membrane:

Phospholipids and proteins

The bonds between the hydrogen atoms and the oxygen atom in a water molecule are:

Polar covalent bonds

Which of the following characteristics, structures, or processes is common to both bacteria and viruses:

Genetic material composed of nucleic acid

When a hypothesis is tested which of the two following outcomes is possible:

The hypothesis is corroborated or falsified

Hydrophobic substances such as vegetable oil are:

Nonpolar substances that repel water

Hydrogen bonds:

These are non-covalent bonds, caused by the attraction of, say, the slightly negative side of one water molecule to the slightly positive side of another water molecule. Hydrogen bonds are extremely important in determining the nature of water

Ionic bonds:

A strongly electronegative atom, such as chlorine, takes the electron from sodium into its own outer valence shell. Salts tend to be ionically-bonded substances. They are crystalline when solid, and separate into cations and anions when in solution.

In a solution of sodium chloride:

the Na+ is the cation, the Cl- is the anion

Anions are:

negatively charged ions

Cations are:

positvely charged ions

The seven functional groups that are most important in the chemistry of life:

Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl group

Amino and carboxyl functional groups are always present on an:

amino acid

Four of water’s properties that facilitate an environment for life are:

cohesive behavior, ability to moderate temperature, expansion upon freezing, versatility as a solvent

Cohesive behavior -

strong ability to attract and stick to other water molecules, primarily due to the formation of hydrogen bonds between them

Ability to moderate temperature -

Water has a high heat capacity, meaning it can absorb and release heat with only small changes in temperature

Expansion upon freezing -

Water's unique expansion upon freezing, which makes ice less dense and causes it to float, is crucial for aquatic life, as it insulates bodies of water and prevents them from freezing solid

Versatility as a solvent -

rooted in its polar molecular structure and ability to form hydrogen bonds, allowing it to dissolve a wide range of polar and ionic substances crucial for life and industry

The formation of bonds with carbon:

With four valence electrons, carbon can form four covalent bonds with a variety of atoms; This tetravalence makes large, complex molecules possible

The importance of carbon:

Although cells are 70-95% water, the rest consists mostly of carbon-based compounds; Carbon is unparalleled in its ability to form large, complex, and diverse molecules; Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds

Oxygenic atmosphere:

An oxygenic atmosphere evolved (2.0-0.5 billion years ago); The early rise in O2 was likely caused by ancient cyanobacteria; A later increase in the rise of O2 might have been caused by the evolution of eukaryotic cells containing chloroplasts

Why are hydrocarbons insoluble in water? Think about hydrogen bonding opportunities… :

Hydrocarbons are insoluble in water because they are nonpolar molecules, lacking the ability to form strong hydrogen bonds with polar water molecules; water can only effectively dissolve other polar substances capable of forming hydrogen bonds, not nonpolar hydrocarbons

The molecule ethane has the formula CH2CH2. The molecule ethanol has the formula CH2CHOH. Which one is water-soluble in water, and why:

Ethanol is water-soluble because it is a polar molecule, meaning it has a slight positive end and a slight negative end. The key to its solubility is the presence of the hydroxyl group (-OH), which can form strong hydrogen bonds with the water molecules

What makes water so important for life as we know it on planet Earth:

Water is vital for life on Earth because it acts as a universal solvent, enabling necessary chemical reactions and transporting nutrients and waste within cells and the environment. Its unique properties, including cohesion, adhesion, and a high specific heat capacity, help regulate temperature and facilitate water transport throughout organisms like plants

Why are people who are on a gluten-free diet so agitated:

Peptides produced by the digestion of gluten give us a happy feeling from exogenous morphine.