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Cells becoming resistant to bacteria; Within a population of bacteria, NO cells are resistant to antibiotics. Over time, ALL cells are resistant to antibiotics. Outline the steps of natural selection that lead to a fully resistant population:

Within the bacterial population, the cells obtain different types of mutations. - One type of mutation is antibiotic resistance. - Some types of mutations are harmful to the cell, some have no or li...

Answered by Emmaline S. • Biology tutor

1998 Views

How many chromosomes dies each cell of the human body have ?

All human body cells have 23 pairs of chromosomes (46 total), 22 pair of autosomes and 1 pair of sex chromosomes.

However, sperm and egg cells only have one set of chromosomes (23 total).

Answered by Helen K. • Biology tutor

5143 Views

What are three differences between DNA and RNA? ( 3 marks)

RNA is single stranded whereas DNA is double stranded - RNA has the bases A,G,C and U whereas DNA has the bases A,G,C and T - An RNA nucleotide has ribose as its sugar component whereas a DNA nucleo...

Answered by Prahalad N. • Biology tutor

2877 Views

It has been suggested that smoking, an epigenetic factor can lead to tumour growth and cancer. Use your knowledge of the epigenome and its structure to explain how this could occur. [5 marks]

Marking Scheme: MP1: Define epigenome- layers of chemical tags covering the DNA and histone protein complex MP2: Increased Methylation of DNA molecule MP...

Answered by Hannah H. • Biology tutor

2688 Views

The Polar Bear is the largest species of bear in the world. With regards to adaptation, suggest a reason for this.

The habitat of the Polar Bears is the arctic. This is a much colder climate than the other species of bear found in the wild. Therefore the Polar Bear has adapted to live in this colder climate. One adapt...

Answered by Zia F. • Biology tutor

5905 Views