Nature of Science and the Building Blocks of Life

Which of the following characteristics of carbon makes it a good building block for molecules?

• Carbon can easily transfer its electrons to other atoms
• Carbon forms both covalent and ionic bonds
• Carbon has four valence electrons and can share electrons with many atoms
• Carbon easily reacts with water to form solutions in living things

Attractions between the negative end of one water molecule and the positive end of a different water molecule are called

• Covalent bonds
• Ionic bonds
• Polar bonds
• Hydrogen bonds

Why does ice float?

• As water freezes, it expands and its density decreases.
• As water freezes, it takes up more hydrogen from the atmosphere, causing it to have a greater buoyancy.
• As water freezes, more hydrogen bonds form, making ice float
• As water freezes, it takes up more oxygen from the atmosphere, causing it to have a greater buoyancy.

Tags

NGSS.MS-PS1-4

Which end of the water molecule has a slightly positive charge?

• the oxygen end
• the hydrogen end
• both ends are slightly positive
• neither end is positive

Tags

NGSS.HS-PS1-3

Water is polar because...

• The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.
• The molecule has two poles, at which the it is colder than other regions of the molecule.
• The unequal sharing of electrons gives the water molecule a slight negative charge near its hydrogen atoms and a slight positive charge near its oxygen atom.
• The water molecule is neutral.

What word describes when water is attracted to other substances?

• cohesion
• adhesion
• capillary action
• surface tension

A water strider can skate along the top of a pond because:

• covalent bonds result in water cohesion
• hydrogen bonds result in water cohesion (surface tension)
• water striders have special powers
• low surface tension of water

DNA and RNA are examples of...

• lipids
• carbohydrates
• proteins
• nucleic acids

What is the function of nucleic acids?

• Stores energy
• Stores genetic information
• Movement
• Physical structure

Lipids are made up of which of the following?

• glycerol and fatty acids
• glycerol and monolipids
• fatty acids and phosolipids
• amino acids and nucleotides