1. Answer: A
Explanation: For a cell to form proteins, the specific types of proteins are coded for by the genes in DNA (found in the chromosomes of the nucleus). To produce proteins, the genes are first transcribed by RNA polymerase to form messenger-RNA. The mRNA is then translated into proteins by ribosomes in the cytoplasm of the cell.
2. Answer: B
Explanation: Translation of genes into proteins is dependent on the sequence of nucleotides. They are translated in sequences of 3 nucleotides known as codons. Therefore adding a nucleotide on a piece of DNA causes what is referred to as a frame-shift mutation. The 3 sequences (of codons) is interrupted and shifted by one nucleotide. Therefore, the codons change and the amino acids translated will also change.
3. Answer: A
Expanation: Producers are significant in a food chain because they incorporate the energy of the sun into the food chain. This is why they are at the base of the food chain and have the largest biomass. They are consumed by primary consumers which are consumed by secondary consumers which are consumed by tertiary consumers and so on.
4. Answer: D
Explanation: Plants are consumed by herbivores. Therefore, a decrease in plant population due to drought was resulted to decrease in herbivore population. This is due to stiff competition by the herbivores for the scarce plant population. Carnivores consume herbivores. Due to a decrease in the herbivore population, then the carnivore population would also decrease.
5. Answer: A
Explanation: Burning of fossil fuels emits carbon dioxide gas which is a greenhouse gas. Greenhouse gas traps infrared wavelength of lights hence warming up the atmosphere, causing global warming. Reduction in use of fossil fuels will hence alleviate an increase in global temperature hence protect coral in the oceans from bleaching.
Answer:Airedale Terrier is a Dog specie,the Airedale Terrier is the largest of all terrier breeds.
(1) Respiration
(2) Nutrition
(3) Reproduction
(4) Movement
(5) Irritability
Explanation: A living specie is a specie that poses all the characteristics of a living organisms such MOVEMENT, REPRODUCTION, NUTRITION, IRRITABILITY,GROWTH, EXCRETION, REPRODUCTION AND DEATH.
Respiration is the process through which living organisms take in oxygen in order to break down food for the release of energy and carbon dioxide.
Nutrition is the process of feeding or intake of nutrients Airedale Terrier feeds on both plants and animals ( OMNIVORES).
Reproduction is the process through which the younger generation are brought to life Airedale Terrier reproduce through Sexual reproduction.
Movement is the change of location,Airedale Terrier moves from one point to another.
Airedale Terrier responds to different stimuli ranging from sound,light,touch, taste etc.
This is parasitism because one organism (mosquito) is benefitting (by acquiring nutrition) and the other organism (human) is harmed (by the red itchy bump).
<h2>Given statement is false</h2>
Explanation:
According to dispersive model of DNA replication,DNA molecules are hybrids of parental and daughter DNA;In this model each individual strand is a combination of original and new DNA
Meselson and Stahl did an experiment on DNA replication using E.coli bacteria
- E.coli was grown in a medium containing heavy isotope of nitrogen,bacteria took up the nitrogen and used to synthesize new biological molecules,including DNA
- It was grown for many generations,the nitrogenous bases of the bacteria's DNA were all labelled with heavy nitrogen
- Bacteria were then switched to light nitrogen isotope and allowed to grow for several generations
- They then measured the density of the DNA using density gradient centrifugation
- This method separates molecules such as DNA into bands by spinning them at high speeds in the presence of another molecule, such as cesium chloride
- Each DNA produced two DNA molecules each with one new strand and one old strand called semi conservative replication(half of the parental DNA conserved in daughter DNA)
- Each DNA strand act as a template for synthesis of new strand
- Hence,dispersive model of DNA was eliminated and semi-conservative model of DNA replication was proved by the above experiment
There are a variety of points in the transcriptional chain at which it is possible to disrupt protein synthesis in bacteria. Let’s enumerate just a few:
<span>There’s the initial point where DNA is transcribed into mRNA;<span>there’s the point where mRNA binds to the Ribosome complex;</span>there’s the point where tRNA-aminoacyl pair binds to the Ribosome according to the current codon being “read out” in the mRNA;there’s the point where the aminoacid transported by the tRNA is transferred to the growing protein chain; andthere’s the point where the protein synthesis is determined complete, and the Ribosome disengages and releases the newly-synthesized peptide chain.</span>
In each of these stages (and in some other, more subtle phases) there are possible points of disruption and there are specific disruptors; some of which are indicated in the aboveProtein synthesis inhibitor article.
Note, by the way, that the Ribosomes of Prokaryotes (bacteria) and Eukaryotes (cells with nuclei) aren’t identical, and therefore the inhibitors/disruptors that work for one type of cell may not (and usually don’t) work on the other type. That’s why we can take antibiotics targeted at bacteria with little to no fear of them interfering with our eukaryotic cells’ functions.
(This is a simplified, somewhat hand-wavy response. There is a lot more to say, mainly because biological systems are anything but simple. Nevertheless this should be enough to get you started in the general direction.)
