What two molecules make up a chromosome?
What two molecules make up a chromosome?
Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA).
What type of molecules are produced using DNA?
What does DNA do? DNA contains the instructions needed for an organism to develop, survive and reproduce. To carry out these functions, DNA sequences must be converted into messages that can be used to produce proteins, which are the complex molecules that do most of the work in our bodies.
What are the four molecules of DNA?
DNA is a linear molecule composed of four types of smaller chemical molecules called nucleotide bases: adenine (A), cytosine (C), guanine (G), and thymine (T).
What does DNA attach to?
sugar-phosphate backbone
What are the 5 steps of DNA replication in order?
- Step 1: Replication Fork Formation. Before DNA can be replicated, the double stranded molecule must be “unzipped” into two single strands.
- Step 2: Primer Binding. The leading strand is the simplest to replicate.
- Step 3: Elongation.
- Step 4: Termination.
What is the order of DNA replication?
Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment. During separation, the two strands of the DNA double helix uncoil at a specific location called the origin.
Why are they called Okazaki fragments?
Word origin: named after its discoverers, Reiji Okazaki and his wife, Tsuneko Okazaki, while studying replication of bacteriophage DNA in Escherichia coli in 1968.
Why do Okazaki fragments occur?
Discontinuous Replication Generates Okazaki Fragments Because DNA polymerases cannot initiate DNA synthesis, each Okazaki fragment is primed with a short RNA.
What is the importance of Okazaki fragments?
Therefore, efficient processing of Okazaki fragments is vital for DNA replication and cell proliferation. During this process, primase-synthesized RNA/DNA primers are removed, and Okazaki fragments are joined into an intact lagging strand DNA.
What is the purpose of Okazaki fragments quizlet?
Okazaki fragments are short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections.
What enzyme joins Okazaki fragments together?
DNA ligase
Why are Okazaki fragments discontinuous?
On the upper lagging strand, synthesis is discontinuous, since new RNA primers must be added as opening of the replication fork continues to expose new template. This produces a series of disconnected Okazaki fragments.
What are the 2 strands of DNA called?
The DNA molecule consists of two strands that wind around one another to form a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
Why does DNA synthesis occur in the 5 ‘- 3 direction?
DNA is always synthesized in the 5′-to-3′ direction, meaning that nucleotides are added only to the 3′ end of the growing strand. As shown in Figure 2, the 5′-phosphate group of the new nucleotide binds to the 3′-OH group of the last nucleotide of the growing strand. Two phosphates are cleaved off.
Do you read DNA from 5 to 3?
5′ – 3′ direction refers to the orientation of nucleotides of a single strand of DNA or RNA. DNA is always read in the 5′ to 3′ direction, and hence you would start reading from the free phosphate and finish at the free hydroxyl group.
How are DNA strands read?
DNA is ‘read’ in a specific direction, just like letters and words in the English language are read from left to right. 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).
Why does DNA have 6 reading frames?
And when that happens, it confuses the ribosome, and the ribosome stops. So you’ll be pleased to hear that codons, which make that happen are called stop codons, and a stop codon ends an open reading frame. So it’s actually six different reading frames for every piece of DNA, which might give you an open reading frame.
What is called codon?
A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis. Each codon corresponds to a single amino acid (or stop signal), and the full set of codons is called the genetic code.
Is tRNA the same as DNA?
During transcription, a messenger ribonucleic acid, or mRNA, is created from the DNA template. This mRNA combines with a ribosomal RNA, known as rRNA, and transfer RNA, or tRNA, complex to translate the mRNA code into an amino acid sequence, a protein. DNA is made up of a sequence of nucleotide bases.