Problem 1 - Biology Today and Tomorrow with Physiology

Question

A chromosome contains many genes that are transcribed into different _____________. a. proteins b. polypeptides c. RNAs d. a and b

Step-by-Step Solution

Answer

The answer is c. RNAs.

Step 1: Understanding Chromosomes and Genes

A chromosome is a structure within cells that contains many genes. Each gene serves as a blueprint that can be transcribed into RNA molecules. This is the first step in the expression of biological information. Only few of these transcribed RNA molecules are further translated into proteins.

Step 2: Transcription Stage

The process where genes in the chromosome are copied into RNA is known as transcription. Thus, chromosomes harbor genes that are primarily transcribed into RNAs. Not all RNA gets translated; some perform functions directly as RNA.

Step 3: Considering the Options

Option 'a' refers to proteins which are the ultimate product of the central dogma of biology but not directly transcribed. Option 'b', polypeptides, are chains of amino acids and result from translating RNA. Option 'c', RNAs are direct products of transcription, matching the question directly. Option 'd' can be disregarded as it deals with translation, not directly transcription.

Key Concepts

Chromosomes

Chromosomes are like little libraries inside the cells. Each chromosome is a tightly packed structure made up of DNA and proteins. You can think of it as a bundle of neatly stacked books where the information is stored. Each book is a gene that holds instructions for making the building blocks of life. These books are crucial because they are the blueprints that the cell uses to understand what to make and when. But, how does the information from these books get used by the cell? This is where transcription comes into play.

• Chromosomes serve as storage for many genes.
• Each gene in the chromosome can be thought of as a unique instruction manual.
• This structure is vital for the genetic make-up and functioning of all living cells.

The information in chromosomes flows from DNA to RNA, which then impacts the cell's workings.

RNA

RNA, or ribonucleic acid, is a crucial molecule that acts as a messenger. Created during transcription, RNA carries the genetic code from DNA, directing the manufacture of proteins. It is composed of nucleotides, similar to DNA, but with a few key differences. Unlike DNA, RNA is usually single-stranded and has a different sugar backbone and a unique base called uracil.

• RNA serves as a copy of the gene information.
• It translates genetic instructions into the cell's language.
• There are different types of RNA including mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA), each with unique roles.

RNA does everything from carrying codes for amino acids to being part of the cell's machinery itself.

Transcription Process

The transcription process is how the cell accesses and uses the information in chromosomes. It is like a detailed copying process where the message in a DNA gene is transcribed into RNA. This can be compared to copying text from a book written in one language into another language that the cell machinery can understand and use.

• The enzyme RNA polymerase attaches to the DNA at the start of a gene.
• It moves along the DNA, unwinding the double helix and reading the gene.
• As it moves, it creates a complementary RNA strand from the DNA template.
• Once the entire gene is transcribed, the RNA strand detaches and the DNA rewinds.

This RNA will go on to play various roles in the cell, with some RNA used directly in cellular functions, while others inform the production of proteins through translation.