Before starting the explanation in the amoeba sister video, they explain what DNA replication is. We can say that DNA, which in eukaryotic cells is located in the nucleus, contains all the genetic information of a being and its duplication process is important for cell growth, reproduction and repair.
<h3 /><h3>What is DNA replication?</h3>
A DNA molecule is made up of two strands that complement each other. For example, if we have an F and an F' strand, in the replication process the strands separate and are used as templates for the formation of complementary strands. Thus, the nucleotide sequence of F determines the sequence of a new F' strand, and F' indicates the composition of a new F strand.
<h3>DNA replication process</h3>
In the video of the amoebas sisters it is briefly explained that..
- DNA replication occurs in the 5' → 3' direction and the strands are separated by the action of enzymes, which break the bonds between the nitrogenous bases and unwind the strands, opening the double helix.
- As DNA uncoiling takes place, other enzymes act to catalyze the synthesis of two new sequences using the parent strands as a template. Each strand created joins an original strand of DNA. Therefore, the process is classified as semi-conservative.
- DNA is a double helix molecule and for its duplication to occur, the first step is to unpack this structure by the action of the DNA helicase enzyme. The helicase recognizes the origin of replication and works by breaking the hydrogen bonds in the nitrogenous bases A-T and C-G. This process occurs at several points and forms "replication bubbles".
- As the bonds unravel, it's like a zipper opening, so this step gives rise to a Y-shaped structure called the replication fork, the starting point of duplication.
- The primase enzyme is responsible for synthesizing a portion of RNA, called a primer. In this step, several primers are generated and are joined to the chain to start DNA synthesis.
- The DNA polymerase enzyme is the replication enzyme responsible for extending the new strand by adding the bases (A, C, G and T). This step is directed from the 5' end, with a phosphate group, to the 3' end, with a hydroxyl group. This phase is called continuous replication.
- Among the primers attached to the original strand, several pieces of DNA are attached and are called Okazaki fragments. As the sections will need to be joined later, this phase is called delayed.
- The exonuclease enzyme is responsible for removing the primers from the original strands after the formation of continuous and discontinuous strands. To avoid sequencing errors, a review and, if necessary, a correction is performed by another exonuclease.
- The enzyme DNA ligase causes the DNA fragments to be joined and the DNA sequenced into two continuous strands.
thus, in a simple way, how DNA replication occurs in the video of the amoebas sisters.
learn more about DNA in brainly.com/question/264225?referrer=searchResults
Answer:
The movement of the replication fork is accomplished by the enzyme helicase, which breaks hydrogen bonds between the paired bases and unwinds the double helix ahead of the advancing DNA polymerase.
The last structure the air will pass through will be External nares
<u>Explanation:</u>
The upper portion of the respiratory tract is the nasal cavity and the nose. The external nose forms the first and foremost respiratory tract area. Nose is the major part that is responsible in exchanging air with the atmosphere. It is responsible for the human survival.
There are two openings in a nose. These are called as nostrils. They are also called as exterior nares. The air from the atmosphere when inhaled it enters into the nostril. from there is is sent to the nasal cavity. Nasal cavity is the place where the air that is inhaled will be purified and it is transported to various human parts. thus, when air contains any dust or impurities it will make you to sneeze thereby the air gets out of the nose through External nares
Answer:
1- Option A) describes an index fossil. Trilobite existed for a short time, but was abundant and lived in many locations.
2- Option B) Continents were once joined and have since drifted apart.
Explanation:
1) Fossils are animal and vegetable rests found in different strata of sedimentary rocks. Sedimentary layers deposit chronologically, so they are used to reflect history. They keep in each layer some of the forms of life that inhabited that area in the past. These fossils turn to be very useful while dating ages. The term Index fossils refer to those fossils that only existed in a given era or geological period during evolution.
Index fossils must:
• Be easily recognizable and distinguishable from all the other fossils
• Have lived in a relatively short geological period
• Present a wide geographic distribution
• Have lived in different sedimentary basins
• Appear in different types of rocks
• Be abundant
<em>A) Trilobite existed for a short time, but was abundant and lived in many locations. </em>The species accomplish the requirements. It is easily recognizable, had a wide geographic distribution, was abundant, and lived for a short time.
2) The tectonic plates theory states that there is a continual movement of the crust. It explains the movement of the different plates and their directions and interactions. The continental drift theory explains how these movements have been taking place since millions of years ago. When continents were together in a unique continent, many species used to inhabit it. When plates started to separate, they took some of these species that got apart by the ocean. Some species were already dead and fossilized, while some other organisms died during continental drift and got fossilized after the divergence. <em>The existence of the same fossils, placed in the same layers and of the same age, suggests that they used to inhabit the same area and died during the same time, meaning that continents were together when they got fossilized. </em>
Answer: c cuvuyvuygv jghvhghv hjhcv86 rdf rt6fyc f cututrcut fyiuiyc vjycf g
Explanation:
