Understanding Nucleic Acids, Genetics, and Cellular Biology

Bright Cyclic Electron Flow

The electrons freed after reaching ferredoxin are passed to plastoquinone and follow the electron transport chain to return to the plastocyanin and photosystem I.

Nucleic Acids

Nucleic acids are macromolecules composed of repeating polymers of monomers called nucleotides linked by phosphodiester bonds.

Types of Nucleic Acids

• The sugar (pentose) present: deoxyribose in DNA and ribose in RNA.
• The nitrogen-containing bases: adenine, guanine, cytosine, and thymine in DNA; adenine, guanine, cytosine, and uracil in RNA.
• In eukaryotes, DNA has a double-stranded structure, while RNA is typically single-stranded. RNA can occur in extended form, such as mRNA, or in folded form, such as tRNA and rRNA.
• The molecular mass of DNA is generally greater than that of RNA.

Ribosomal RNA (rRNA)

Ribosomal RNA consists of a single chain of nucleotides, although it has double-stranded regions due to its three-dimensional conformation.

Genetic Code

The genetic code is the rule of correspondence between the sequence of nucleotides in nucleic acids and the sequence of amino acids in polypeptides (proteins).

Homozygous

When an organism is homozygous for a specific gene, it means it has two identical copies of that gene for a given trait on both homologous chromosomes.

Heterozygote

A heterozygote is a diploid individual that has different alleles for a given gene (locus) on each of the two homologous chromosomes.

Karyotype

A karyotype is the arrangement of metaphase chromosomes in a cell based on their morphology, such as size, arm ratio depending on the primary constriction, and the presence of secondary constrictions.

Diploid

Diploid cells have a double number of chromosomes, in contrast to a gamete, meaning they have two sets of chromosomes.

Haploid

A haploid cell contains a single set of chromosomes or half (n, haploid) the normal number of chromosomes found in a diploid cell.

Somatic Cell

Somatic cells are those that make up the tissues and organs of a living being, originating from stem cells during embryonic development. They undergo a process of cell proliferation, cell differentiation, and apoptosis.

DNA

DNA is a type of nucleic acid, a macromolecule that is part of every cell.

RNA

RNA is a nucleic acid comprising a long chain of nucleotides.

Messenger RNA (mRNA)

Messenger RNA acts as a messenger to the cytoplasm, and hence to the ribosome, which is the physical location for translating genes into proteins.

Transfer RNA (tRNA)

Transfer RNA is a form of ribonucleic acid responsible for transporting amino acids to ribosomes for incorporation into proteins during protein synthesis.

Ribosomal RNA (rRNA)

Ribosomal RNA consists of a single chain of nucleotides, although it has double-stranded regions due to its three-dimensional conformation.

Base Pairing Rules

• Messenger RNA (mRNA): Adenine pairs with Thymine, and Cytosine pairs with Guanine.
• Transfer RNA (tRNA): Adenine pairs with Uracil, and Cytosine pairs with Guanine.