CHAPT5.5 APBIO

The amino acid sequence of a polypeptide is programmed by a discrete unit of inheritance known as a ____

Gene

Unique among molecules, DNA provides directions for its own replication. DNA also directs RNA synthesis and, through RNA, controls protein synthesis; this entire process is called ____ ______

gene expressoin

Nucleic acids are polymers made of monomers called ______.

nucleotides

_____ is the genetic material that organisms inherit from their parents.

DNA

The information that programs all the cell’s activities is encoded in the structure of the ____.

DNA

A given gene along a DNA molecule can direct synthesis of a type of RNA called ______ RNA (mRNA).

messenger

The sites of protein synthesis are cellular structures called _______.

ribosomes

In a eukaryotic cell, ribosomes are in the cytoplasm but DNA is in the nucleus. How does DNA give genetic directions for protein synthesis

It uses mRNA to convey the message

Nucleic acids are polymers called polynucleotides. As indicated by the name, each polynucleotide consists of monomers called _______

nucleotides

A nucleotide, in general, is composed of three parts: 1.__ 2.___ 3._____

a five-carbon sugar (a pentose), a nitrogen-containing (nitrogenous) base, and one to three phosphate group.

The beginning monomer used to build a polynucleotide has _____ phosphate groups, but two are lost during the polymerization process. The portion of a nucleotide without any phosphate groups is called a ______.

three,nucleosides

Each nitrogenous base has ___ or ___ rings that include nitrogen atoms

There are two families of nitrogenous bases: _____ and ____________

one or two

pyrimidines and purines

A ______ has one six-membered ring of carbon and nitrogen atoms. The members of the pyrimidine family are___ ___ ___

pyrimidine,cytosine (C), thymine (T), and uracil (U)

______ are larger, with a six-membered ring fused to a five-membered ring. The ____ are___ and ____

purines,purines,adenine (A) and guanine (G).

In DNA the sugar is _______; in RNA it is _____ (see Figure 5.23c). The only difference between these two sugars is that deoxyribose lacks an _____ atom on the second carbon in the ring

deoxyribose,deoxyribose,oxygen

To complete the construction of a nucleotide, we attach one to three phosphate groups to the ___′ carbon of the sugar (the carbon numbers in the sugar include′, the prime symbol

5

In the polynucleotide, adjacent nucleotides are joined by a _____ ____, which consists of a phosphate group that covalently links the sugars of two nucleotides.

phosphodiester linkage

This bonding results in a repeating pattern of sugar-phosphate units called the sugar-phosphate backbone (see Figure 5.23a). (Note that the ______ bases are not part of the backbone-the bases are attached along the backbone)

nitrogeneous

the two ends of a backbone are different,One end has a phosphate attached to a 5′ carbon, and the other end has a hydroxyl group on a 3′ carbon; we refer to these as the _′ end and the _ end, respectively.

5,3

DNA molecules have two polynucleotides spiraling around an imaginary axis, forming a ____ _____

double helix

The backbones urn in opposite 5’→3’ direction from each other, an arrangement called _____

antiparallel

Only certain bases in DNA pair up and form hydrogen bonds: adenine always with thymine and guanine always with cytosine(this is called _______

complementary base pairing

Thise feature of DNA structure makes it possible to generate two identical copies of each ___ molecule in a cell preparing to divide

DNA

RNA in contracts to DNA is ____-_______

single stranded

__________ ____ can also occur btwn two RNA molecules or between parts for the same moleucle

complementary pairing

In RNA thymine is replaced by uracil(U), so A and U ___

pair

while DNA always exists as a double helix, ___ molecules are more variable in form

RNA