Nucleotides - created from Mind Map

Página 1

DNA

RNA

BACTERIA

GENETIC CODE

GENES

CHROMOSOMES

CtDNA AND mtDNA

Deoxyribonucleic acid

consists of a double strand of nucleotides held together by pairs of nitrogenous bases

capable of replicating and determining the inheritance of cell's proteins

NITROGENOUS BASES

Role

basic functional unit of a DNA molecule that contributes to the inheritance of characteristics

sequence of nucleotides that codes for a protein

three nucleotides code for one amino acid therefore many code for a protein

strand of DNA and associated proteins (histones)/ It contains the genes at different loci

loci - sites on a chromosomes where a particular gene is located

Alleles - one of different versions of the same gene (at the same locus) determined by small differences in the nucleotide sequence of genes

Chromatin - aggregate mass of dispersed genetic material, formed of protein and DNA, found in eukaryotic cells in the interphase stage

chromatid - replicated chromosome, still attached to the original at the centromere

In a cell undergoing mitosis/meiosis, the normal chromosome has replicated itself (hence 2 chromatids) and the chromosome becomes visible

each species has a characteristic number of chromosomes. The chromosomes in every cell of the body are identical, with the exception of the gametes (1/2 the normal number)

Homologous chromosomes - pair of chromosomes that have the same size, shape and genes at the same location

Karyotypes - pictures of the chromosomes of a cell arranged in relation to size, shape and number

Autosomes - chromosomes other than sex chromosomes

Sex chromosomes - chromosomes carrying information which determines the sex of an individual - an exception to the rule on homologous chromosoems

Haploid

Diploid

Histones assist in packaging in the DNA so that it can fit into the nucelus

prior to cell division, the chromatin is at its most compact, forming the condensed chromosomes that can be seen with a light microscope

appear dark blue when stained

humans - 46 - 23 gametes

one chromosome or each pair has come from the father and the other from the mother

having a single unpaired set (n) of chromosomes eg. gametes

having two (paired) sets of chromosomes (2n)

both mitochondrion and chloroplasts are semi-autonomous organelles with DNA

majority of proteins required for mitochondrion and chloroplast are coded by genes of the nucleus, however, some proteins required for proper functioning are coded for by the DNA for mitochondrion and chloroplast - hence why semi-autonomous

in most multicellular organisms, the mtDNA and ctDNA is organized as a circular, double-stranded DNA

mtDNA

in most species, inclusing humans, mtDNA is inherited solely from the mother

since mtDNA evolves relatively slowly compared to other genetic markers, it is of importance to phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations

Deoxyribose is a five-carbon sugar

5 carbon atoms

Numbered 1'-5'

In an individual nucleotide, a phosphate is attached to the 5' carbon, and a base is attached to the 1' carbon

The 2 ends of the polynucleotide chain are known as an are referred to as the 5' and 3' ends

The 2 strands of DNA molecule are antiparallel i.e. one strand runs 5' to 3' and the other 3' to 5'

complimentary paris and they will only pair in a certain way

A - T(U in RNA) and C-G

order of bases = genetic code

sequence of 3 bases is the code for a particular amino acid EG. C-A-G - 'valine'

in determining the strcutre and function of the cell by controlling the production of proteins through the activation of parts of the DNA

Ribonucleic acid

consists of a single strand of nucleotides linked together

prokaryotics chromosome is not enclosed in a nuclear membrane and is not associated with a protein.

bacteria also often contains other small, circular double-stranded DNA molecules called plasmids

single, circular molecule of double stranded DNA which is in direct contact with the cytoplasm

independent of the main bacterial chromosome and usually contain genes that are not crucial to cell survival under normal conditions

can replicate independently from the main chromosome and have become important tools in genetic engineering because they are easily transferred from one bacterium to another and replicate rapidly

the sequence of nucleotides in DNA is the genetic code

Codon = triplet code; 1 codon codes for a specific amino acid (some redundancy in code protects from the effect of some mutations)

each gene codes for a specific message, often a protein (enzyme)

The universal genetic code is the sequence of nucleotides in DNA or RNA that determines the specific amino acid sequence in the synthesis of proteins in nearly all organisms.

proteins

organic compounds which contain carbon, nitrogen, hydrogen and oxygen

proteins are made up of subunits called amino acids of which there are about 20 types

amino acids join together to form long chains of molecules called polypeptides

a protein is composed of one or more polypeptides folded to form a complex 3D shape

the sequence of amino acids will determine the proteins shape and therefore function

serve critical roles in the cellular structure, function and development of a cell as proteins form

Everything a cell does (what it develops into, what it synthesises and how it operates) is determined predominantly by the proteins it expresses.