Genes, DNA, RNA, and Protein Synthesis Review

Flashcards covering key concepts from the lecture on genes, DNA, RNA, protein synthesis, and lactose intolerance.

What is the discrete unit of inheritance that programs the sequence of a polypeptide?

A gene

What do genes primarily consist of?

DNA (deoxyribonucleic acid)

From whom is DNA typically inherited?

An organism's parents

What are two critical functions of DNA regarding cellular activity?

It provides directions for its own replication and programs a cell's activities by directing the synthesis of protein.

What intermediary molecule does DNA use to direct protein synthesis, as it does not build proteins directly?

RNA (ribonucleic acid)

Where do the processes of transcription (DNA to RNA) and translation (RNA to protein) occur within a cell?

Transcription occurs in the cell's nucleus, and translation occurs in the cytoplasm.

What are the monomers that compose DNA and RNA?

Nucleotides

What are the three main components of a nucleotide?

A five-carbon sugar, a phosphate group, and a nitrogenous base

What are the names of the five-carbon sugars found in RNA and DNA, respectively?

Ribose in RNA and deoxyribose in DNA

What are the four nitrogenous bases found in DNA?

Adenine, thymine, cytosine, and guanine

What are the four nitrogenous bases found in RNA?

Adenine, uracil, cytosine, and guanine

Which nitrogenous base replaces thymine in RNA?

Uracil

How do nucleotide monomers link to form a polynucleotide?

The phosphate of one nucleotide bonds to the sugar of the next nucleotide via dehydration reactions.

What repeating structure is formed by the linkage of sugars and phosphates in a polynucleotide?

A sugar-phosphate backbone

What is the typical structure of an RNA molecule?

A single polynucleotide strand

What is the typical structure of a DNA molecule?

A double helix in which two polynucleotide strands wrap around each other

How do the two strands of a DNA double helix associate with each other?

Through hydrogen bonding between particular nitrogenous bases

What are the specific base pairing rules for DNA?

Adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G).

Which base pairs with adenine in RNA?

Uracil

What is the biochemical reason why most adults develop lactose intolerance?

They stop producing the enzyme lactase, which is necessary to digest milk.

From an evolutionary perspective, what does lactose tolerance represent?

A relatively recent mutation in the human genome and a survival advantage for human cultures with milk and dairy products available year-round.

What did researchers discover about lactase persistence in East African populations?

They identified three new mutations, different from each other and from the European mutation, that keep the lactase gene permanently turned on.