A DNA molecule is like a ladder because there are two sides (the sugar-phosphate backbones of the two strands) and rungs (each rung being a pair of complementary bases). Twisted, because the molecule is twined in a coil called a helix - or rather, a double helix because there are two strands.
<u>Answer</u>:- Active transport
<u>Explanation</u>:-
There are two types of membrane transports
1. Passive transport - this type of transport occurs without the input of any energy and the molecules move along the concentration gradients that is from <em>high concetration to low concentration.</em>
2. Active transport- this type of transport takes place to move the molecules against the concentration gradient that is from <em>low concentration to high concentration.</em>
<em>The active transport is of two types:</em>
1. <em>Primary active transport-</em> in this type of transport <em>ATP</em> is used as an energy source to move the substances against the concentration gradient.
2.<em>Secondary active transport</em> - in this type of transport the gradient formed by the active transport is utilized and it involves the movement of 2 substances at a time aross the membrane. That is the movement of one molecule is coupled to another.
- The membrane proteins that are associated with active transport are called as <em>carrier proteins</em>. These proteins have a binding site for the molecules that they transport. Once they bind to the specific molecules, a conformation change is induced and this leads to the transport of the molecule across the membrane.
So, the <em>active transport is basically responsible for utilizing the energy from ATP and carrier proteins to move the substances across the membrane against their concentration gradient i.e. from low concentration to high concentration.</em>
The sole reason why red blood cells are unable to replace damaged proteins is that red blood cells lack DNA and cell organelles such as nucleus, ribosomes and mitochondria which are crucial for protein synthesis, assembly and repair. In other words they lack both the information and the machinery for making or repair of proteins.
Due to lack of DNA and cell organelles, red blood cells cannot be able satisfy the central dogma which summarizes synthesis of proteins as DNA → RNA → proteins.
DNA has the genetic information on how proteins should be made, RNA is responsible for transferring the information from DNA in the cell nucleus to the ribosomes in the cytoplasm, then translating or decoding this information, which results in the making of protein.
Due to human activities, the greenhouse gases are the most substantial mediator of the witnessed climate change since the mid-20th century. Globally, the overall emissions of greenhouse gases due to human activities have upsurged by 35 % from 1990 to 2010.
The concentrations of carbon dioxide and other greenhouse gases in the atmosphere have upsurged since the start of the industrial revolution. Of the greenhouse gases, the fluorinated gases exhibit an average lifetime in the atmosphere of a few weeks to thousands of years.
The fluorinated gases refer to an array of gases, which comprise fluorine, incorporating perfluorocarbons, hydrofluorocarbons, and sulfur hexafluoride, among other chemicals.
These gases are discharged due to numerous industrial procedures and household and commercial applications and do not take place naturally. It is at certain instances used as the substitutes for the ozone-depleting components like CFCs.
Hope this helps at least a little :)
