Related Concept Videos

Lung Capacity 01:47

56.4K

The air in the lungs is measured in volumes and capacities. Lung volume measures reflect the amount of air taken in, released, or left over after a lung function, like a single inhalation. Lung capacity measures are sums of two or more lung volume measures.

There are four defined lung volume measures: tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume.

Tidal volume is the amount of air inhaled and exhaled in a normal breath. Inspiratory...

Overview of DNA Repair 02:25

33.8K

In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...

Phase II Reactions: Methylation Reactions 01:17

747

Methylation is a phase II biotransformation process involving the attachment of a methyl group to a substrate. Enzymes known as methyltransferases orchestrate this reaction.
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...

DNA Topoisomerases 02:02

35.7K

Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. ...

DNA Helicases 00:55

24.2K

DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...

Recombinant DNA 01:09

103.4K

Overview

Scientists create recombinant DNA by combining DNA from different sources—often, other species—in the laboratory. DNA cloning allows researchers to study specific genes by inserting them into easily manipulated cells, such as bacteria. Organisms that contain recombinant DNA are known as genetically modified organisms (GMOs). Recombinant DNA technology produces organisms with new genes that can benefit science, medicine, and agriculture.

How Do Scientists Create...