CHROMOSOMES AND DNA

• In 2003, the Human Genome Project, a global initiative to map the human genome, was finished.

• It resulted in the discovery of more than 20,000 distinct human genes spread over the 46 human chromosomes, which together contain roughly 3.2 billion base pairs.

• Despite the fact that a large portion of the chromosomes' DNA does not code for proteins, this DNA is known as

• Although it is "junk" DNA and non-coding, it may nonetheless control gene activity.

• In contrast to noncoding DNA, junk DNA does not have a structure that is similar to that of genes.

KARYOTYPE

• A karyotype is a picture of every chromosome in a cell in their usual arrangement.

CHROMOSOME COMPLEMENT

• 22 comparable pairs—one from each parent and one from the mother—make up the 46 chromosomes in humans.

• They are numbered 1 (the biggest) to 22. (smallest).

• The sex chromosomes are the 23rd pair, with XX denoting female and XY (as in this case) denoting male.

• Each chromosome exhibits bands known as banding patterns after being treated with chemicals.

CHROMOSOME SEVEN

• With around 159 million base pairs, this chromosome makes up more than 5% of the entire genome.

• With the remainder in the longer arm, 7q, only about 60 million people are in the shorter arm, 7p.

MITOCHONDRIAL GENES

• The mitochondria, the cell's powerhouses, have their own DNA.

• The mitochondrial DNA (mtDNA) is circular, as opposed to the nucleus' linear DNA.

• There are only 37 genes in it that produce the RNA and proteins the mitochondrion needs to function.

• Because mitochondria are present in the egg during fertilization, mitochondrial DNA is unique in that it can only be passed down through the maternal line.

• Due to the high rate of mtDNA mutation, which results in significantly different mtDNA between unrelated persons, this form of DNA has been used to investigate genetic ties and reconnect families.

• Changes in the mtDNA are linked to certain uncommon disorders.

GENETIC CONTROL OF CELLS

• Not all cells have functioning copies of every gene.

• Gene expression is the process by which a gene is able to produce its protein.

• Each gene's expression is regulated by its exposure to substances like growth factors and regulators, which are the byproducts of other genes.

• In the majority of cells, certain genes are "turned on" and express themselves.

• These deal with fundamental procedures like using glucose as fuel.

• Other genes, used to produce specific products like hormones, are "turned off" when not required.

• Genes in cells are turned on and off under various conditions, causing cells to differentiate, or change.

CELLULAR DIFFERENTIATION

• "Generalized" stem cells are the first cells formed when a fertilized egg divides. Preprogrammed instructions start to operate as they proliferate.

• Cells in specific regions of an embryo receive guidance from chemical environment and intercellular interactions to differentiate into tissues like neuron, muscle, and skin.

PRECURSOR CELL

• This has a wide range of cell types it might become.

• While some lines of daughter cells continue to be generalists, others develop into specialists.

SPERM CELL

• brimming with mitochondria, which provide the fuel

MUSCLE CELL

• Cells that are long and thin and contain proteins that contract

NERVE CELL

• A high degree of specialization with regard to both the shape and the connections

EPITHELIAL CELL

• Designed to produce many offspring quickly and then perish

FAT CELL

• Stores energy in case food does not match energy requirements