Molecular genetics

Name: __________________ Topic: Molecular genetics Concepts Summary Notes Nan Hua High School Biology 1 LO: Outline the relationship between DNA, genes and chromosomes ● A chromosome is a rod-shaped structure that is coiled and condensed. It is made up of a deoxyribonucleic acid (DNA) molecule wrapped around proteins (histones). ● DNA is a molecule that carries genetic/ heredity information in the form of genes along its length. ● Genes are small segments of DNA found in a chromosome. Every gene codes for a specific polypeptide, which determines a particular characteristic in the organism. LO: State the structure of DNA in terms of the bases, sugar and phosphate groups found in each of their nucleotides ● The DNA molecule is made up of two strands of polynucleotides twisted around each other to form a double helix. ● Each nucleotide forms the basic unit of DNA. ● The nucleotides are joined up by sugar- phosphate bonds. ● Each nucleotide is made up of a deoxyribose sugar , a phosphate group and a nitrogenous base. ● There are four different ty pes of nitrogenous bases: adenine, cytosine, guanine and thymine.

Name: __________________ Topic: Molecular genetics Concepts Summary Notes Nan Hua High School Biology 2 LO: State the rule of complementary base pairing ● By complementary base pairing, adenine pairs with thymine and cytosine pairs with guanine. ● Except in mRNA where thymine is replaced by uracil.

Name: __________________ Topic: Molecular genetics Concepts Summary Notes Nan Hua High School Biology 3 Differences between DNA and RNA

Name: __________________ Topic: Molecular genetics Concepts Summary Notes Nan Hua High School Biology 4 LO: State that DNA is used to carry the genetic code, which is used to synthesise specific polypeptides (details of transcription and translation are not required) and state that each gene is a sequence of nucleotides, as part of a DNA molecule ● DNA is a molecule that carries genetic information in the form of genes. ● Each gene is made up of a specific sequence of nucleotides of DNA that codes for a specific polypeptide. ● The genetic code on DNA is transcribed to messenger ribonucleic acid (mRNA) in the nucleus. The process is known as transcription. ● The mRNA is translated into a polypeptide in the cytoplasm