Biology Vocab 4

Describes a molecule that has both a water-attracting part and a water-repelling part

Phospholipids are amphipathic molecules because their heads attract water while their tails repel it.

Describes two strands that run in opposite directions alongside each other, as seen in the two strands of a DNA molecule

The two strands of a DNA double helix are antiparallel, meaning they run in opposite directions.

A chemical reaction in which two molecules are joined together by removing a water molecule

Cells use dehydration synthesis to connect amino acids and build proteins.

A type of sugar with five carbons that forms part of the structure of DNA

Deoxyribose is the sugar found in DNA, while ribose is found in RNA.

A sugar molecule made of two monosaccharides joined together by a chemical bond

Sucrose, the sugar you put in your coffee, is a disaccharide made of glucose and fructose.

A chemical bond that connects two sugar molecules together, formed during dehydration synthesis

A glycoside bond links two glucose molecules together to form the disaccharide maltose.

A chemical reaction in which a large molecule is broken apart into smaller molecules by adding water

During digestion, hydrolysis breaks down the starch in bread into individual glucose molecules.

A very large molecule made of many smaller units joined together; proteins, DNA, and carbohydrates are examples

DNA is a macromolecule that carries the genetic information of a living organism.

A photograph or image of a very small object taken through a microscope

The scientist studied a micrograph of the cell to examine the structure of its nucleus.

A small molecule that can join with other identical or similar molecules to form a larger molecule called a polymer

Glucose is a monomer that can be linked together to form the polymer starch.

The simplest form of sugar, made of a single sugar unit that cannot be broken down further by hydrolysis

Glucose and fructose are monosaccharides that provide quick energy for the body.

The basic building block of DNA and RNA, made of a sugar, a phosphate group, and a nitrogen base

Each nucleotide in a DNA strand contains one of four possible nitrogen bases.

A chemical bond that connects the sugar of one nucleotide to the phosphate of the next nucleotide, forming the backbone of DNA and RNA

The phosphodiester bonds in DNA hold the chain of nucleotides together in a stable structure.

A type of lipid molecule that has a phosphate head and two fatty acid tails, and is the main component of cell membranes

Phospholipids arrange themselves into a double layer to form the basic structure of the plasma membrane.

The thin, flexible layer that surrounds a cell and controls what substances enter and leave the cell

The plasma membrane protects the cell and allows nutrients to pass inside while keeping harmful substances out.

A large carbohydrate molecule made of many monosaccharide units linked together

Starch is a polysaccharide that plants use to store energy.

A simple type of cell that does not have a membrane-bound nucleus or other membrane-bound organelles; bacteria are prokaryotic cells

A prokaryotic cell is much simpler than a human cell because it lacks a true nucleus.

A type of nitrogen base found in DNA and RNA that has a double-ring structure; adenine and guanine are purines

Adenine is a purine that always pairs with thymine in a DNA molecule.

A type of nitrogen base found in DNA and RNA that has a single-ring structure; cytosine, thymine, and uracil are pyrimidines

Cytosine is a pyrimidine that pairs with guanine in both DNA and RNA.

A type of fat molecule made of one glycerol unit and three fatty acid chains, used by the body to store energy

Doctors often measure triglyceride levels in the blood to check a patient's heart health.