Concept 19: The DNA molecule is shaped like a twisted ladder. Deoxyribose and phosphate molecules form the uprights and nucleotide pair form the rungs of the DNA ladder.
What molecules make the uprights?
Deoxyribose and phosphoric acid molecules join to form the sides or uprights of the ladder.
What are the uprights of the DNA backbone composed of?
Phosphate Backbone A phosphate backbone is the portion of the DNA double helix that provides structural support to the molecule. DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
What is a rung in DNA?
In DNA, the “rungs” between the two strands of DNA are formed from the nitrogenous bases adenine, thymine, guanine and cytosine. In 1950, Erwin Chargaff published his discovery that the amount of adenine in DNA equals the amount of thymine and the amount of guanine in DNA equals the amount cytosine.
What are the bars in DNA called?
Nucleotides. The basic building block of DNA is called a NUCLEOTIDE. A nucleotide is made up of one sugar molecule, one phosphate molecule and one of the four bases.
What are the rails in the DNA called?
The structure of DNA is a double helix. In other words, it is a double stranded molecule that twists like a spiral staircase. The outsides of the molecule, the railings of the staircase, are made of deoxyribose sugars alternating with phosphates. This part of the molecule is sometimes called the “backbone”.
What substances form the uprights or sides of the DNA ladder?
They showed that alternating deoxyribose and phosphate molecules form the twisted uprights of the DNA ladder.
What holds the two sides of DNA together?
The two strands are held together by hydrogen bonds between pairs of bases: adenine pairs with thymine, and cytosine pairs with guanine.
What are the sides of DNA made of?
The shape of DNA is a double helix, which is like a twisted ladder. The sides of the ladder are made of alternating sugar and phosphate molecules. The sugar is deoxyribose. The rungs of the ladder are pairs of 4 types of nitrogen bases.
Where is the backbone of the DNA?
The backbone of a DNA molecule consists of the phosphate groups and the deoxyribose sugars, whereas the base region of the DNA molecule consists of the nitrogenous bases; therefore, the backbone of DNA is made up of phosphate groups and pentose sugars. Adenine is part of the base region of the molecule.
What are the 4 parts of DNA?
The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people.
What are the sides of DNA molecule called?
Nucleotides are attached together to form two long strands that spiral to create a structure called a double helix. If you think of the double-helix structure as a ladder, the phosphate and sugar molecules would be the sides, while the base pairs would be the rungs.
What are the 4 rungs of the DNA ladder made of?
Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder. (It takes two bases to form a rung — one for each side of the ladder.) A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide.
What are the rungs of the DNA ladder made of quizlet?
The rungs of the DNA ladder are made up of complementary nitrogenous bases and the sides of the ladder are made up of pentose sugars and phosphate groups.
What are the 3 parts of a nucleotide?
- Nitrogenous Base.
- Phosphate Group.
What is 3 end and 5 end in DNA?
Each end of DNA molecule has a number. One end is referred to as 5′ (five prime) and the other end is referred to as 3′ (three prime). The 5′ and 3′ designations refer to the number of carbon atom in a deoxyribose sugar molecule to which a phosphate group bonds.
What constitutes the rails of the DNA quizlet?
DNA is made up of two strands of nucleotides. The nucleotides are made up of a sugar (deoxyribose in DNA), a phosphate, and a nitrogen base. The sugars and phosphates make up the “handrails” (or “backbone”), and are held together by covalent bonds.
What are the rails of DNA made of?
The rails of the DNA strand are made up of deoxyribose (a sugar) and phosphoric acid. These two molecules alternate one after the other the entire length of the rail. The rungs of the DNA strand are made up of organic bases. These organic bases attach to the deoxyribose on the ladder rails.
What parts of the nucleotides make up the sides backbone of the ladder?
What parts of the nucleotides make up the sides (backbone) of the “ladder”? Sugar and phosphate.
How do DNA bases bond together?
The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three. The hydrogen bonding between complementary bases holds the two strands of DNA together.
Why do two strands of DNA stay together?
The two strands of DNA stay together by H bonds that occur between complementary nucleotide base pairs. Two hydrogen bonds occur between the adenosine and the thymine base pairs, and between the cytosine and the guanine there are three.
What bases of DNA always pair together?
Under normal circumstances, the nitrogen-containing bases adenine (A) and thymine (T) pair together, and cytosine (C) and guanine (G) pair together. The binding of these base pairs forms the structure of DNA .
What is A strand of DNA?
DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases: adenine (A), cytosine (C), guanine (G) or thymine (T).
What are the sides of DNA and RNA made up of?
In DNA, the bases are adenine (A), thymine (T), guanine (G), and cytosine (C). In RNA, the bases are adenine, guanine, uracil, and cytosine.
How does A backbone form in DNA?
In double-stranded DNA, the molecular double-helix shape is formed by two linear sugar-phosphate backbones that run opposite each other and twist together in a helical shape. The sugar-phosphate backbone is negatively charged and hydrophilic, which allows the DNA backbone to form bonds with water.