Test yourself

1 In the_-_model of DNA replication, each strand serves as a_for the synthesis of a_stand. Each daughter molecule comprises one_strand and one newly synthesised strand.

2 During DNA replication, the point where the two strands become separated is called the___

3__III forms a second strand by adding complementary nucleotides in the ^ direction.

4 During DNA replication, the__must be synthesised dis-

continuously, as a series of_fragments.

5 Mistakes in DNA replication are largely corrected by the cell's_

enzymes. Any errors that persist may lead to__

6 The function of genes was expressed in the one_, one,_


7 The flow of information: DNA ^ mRNA ^ protein is often referred to as the__of biology.

8 In the genetic code, many amino acids are encoded by more than one triplet sequence; the code is therefore said to be__Three of the_

triplet combinations do not code for an amino acid, but instead serve as _codons.

9 The enzyme RNA polymerase uses a single-stranded_template to synthesise a complementary strand of___

10 Transcription begins at a_sequence, situated_of the gene.

11 In bacteria, proteins with related functions may be encoded together; the result of transcription is a_mRNA.

12 In eukaryotes, genes are usually discontinuous; coding regions called _are interspersed with non-coding__

13 Molecules of tRNA act as adapter molecules during translation; at one end they have a three-base_complementary to a triplet codon, and at the other end carry the corresponding___

14 Lactose acts as an_for the three genes that make up the lac operon.

It neutralises the effects of a_protein encoded by the I gene.

15 The trp operon contains five genes involved in the synthesis of__The presence of this substance activates a_, which prevents transcription of the operon by binding to the_sequence.

16 A_mutation alters the__of a gene and will change the sense of the encoded message. Such a mutation arises through_

or_of DNA.

17 A_mutation changes a normal codon into a_codon, and results in the premature termination of translation.

1 8__such as 5-bromouracil mimic the structure of normal nucleotide bases and become_into the DNA structure.

19 The_test is used to assess the mutagenicity of a substance.

20 In Griffith's famous experiment,__cells of the virulent

S-strain appeared to pass on the ability to synthesise a capsule to the nonvirulent R-strain. Griffith coined the term__for the factor responsible.

21 Transformation only occurs between related cells as it depends on the donor DNA finding a_sequence on the host chromosome with which to

2 2__experiments can be used to map the order in which genes on a bacterial chromosome are transferred by__

23 In_transduction, chromosomal genes close to the point of integration of the_may be excised along with it and be transferred to another host cell.

24 In_transduction, fragments of_DNA are mistakenly packaged into phage coats and can be transferred to another bacterial cell.

2 5__are sequences of DNA that can move from one location on a chromosome to another.

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Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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