Protein Synthesis - Transcription And Translation Biology Worksheet printable pdf download

Protein Synthesis - Transcription And Translation Biology Worksheet

Protein Synthesis- Transcription and Translation

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are nucleic

acids. They are made up of smaller subunits called nucleotides.

Nucleotides are made up of three main parts: a simple sugar (deoxyribose

or D), a phosphate group, and one of four nitrogen bases: adenine (A),

thymine (T), cytosine (C), and guanine (G). The nucleotides in DNA

form two strands, which are held together in the center by the pairing of

nitrogen bases. Nitrogen bases always join (or pair) in the same way.

Thymine always pairs with adenine and cytosine always pairs with

guanine in DNA.

Like DNA, RNA (ribonucleic acid) contains four nitrogen bases,

but instead of thymine, RNA contains a base called uracil (U).

Unlike the double stranded DNA, RNA is made of a single strand of

nucleotides, each of which contains the simple sugar ribose (R).

Transcription

DNA is found only in the cell’s nucleus, and DNA contains the cell’s instructions for

how to make proteins. Proteins are made, however, in the cytoplasm of the cell (by the

ribosomes). The information must somehow leave the nucleus, but DNA is not permitted

to pass through the nuclear membrane. Instead, DNA can be copied into RNA, a copy of

instructions that can leave the nucleus and go to the ribosomes. The process of copying

DNA into RNA is called transcription. (Transcription results in an RNA copy of a

DNA strand.) The main enzyme responsible for transcription is RNA polymerase.

If a strand of DNA is

TAC GCA TCG ATG

its complementary strand of RNA will be

AUG CGU AGC UAC

(Remember that RNA has U instead of T!)

2. Free RNA

nucleotides pair up

with

complementary

1. DNA

DNA bases

molecule is

unzipped

3. A single strand

of RNA is

produced, which

can break away,

leave the nucleus,

and find ribosomes

Protein Synthesis - Transcription And Translation Biology Worksheet