Genetics is the study of genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure and their functions and behaviors. Genetics is an important topic for board examinations, and a thorough understanding Understanding Decision-making Capacity and Legal Competence of different words used in the study of genetics is an important piece of knowledge. Crucial terms in the study of genetics are listed and defined below, in alphabetical order.
Last updated: 4 Jul, 2022
Structure of a chromosome
Image by Lecturio.DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure molecule
Image by Lecturio.
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure polymerase during
translation
Translation
Translation is the process of synthesizing a protein from a messenger RNA (mRNA) transcript. This process is divided into three primary stages: initiation, elongation, and termination. Translation is catalyzed by structures known as ribosomes, which are large complexes of proteins and ribosomal RNA (rRNA).
Stages and Regulation of Translation:
The coding and template strand can be seen. The coding strand is also known as the “sense” strand and the template strand acts as a “template” for
RNA
RNA
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity.
RNA Types and Structure polymerase.
NTPs: nucleoside triphosphates
Human male
karyotype
Karyotype
The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere.
Congenital Malformations of the Female Reproductive System:
A
karyotype
Karyotype
The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere.
Congenital Malformations of the Female Reproductive System is a complete set of matched, homologous
chromosomes
Chromosomes
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell.
DNA Types and Structure (the X chromosome is highlighted).
Comparison of mitosis Mitosis A type of cell nucleus division by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes of the somatic cells of the species. Cell Cycle and meiosis Meiosis The creation of eukaryotic gametes involves a DNA replication phase followed by 2 cellular division stages: meiosis I and meiosis II. Meiosis I separates homologous chromosomes into separate cells (1n, 2c), while meiosis II separates sister chromatids into gametes (1n, 1c). Meiosis
Image by Lecturio.Diagram showing an operon model with regulator, promoter, operator, and structural
genes
Genes
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
DNA Types and Structure:
The operon contains the
genes
Genes
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
DNA Types and Structure of interest.
The promoter is the binding site for certain
proteins
Proteins
Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein.
Energy Homeostasis to allow
initiation of transcription
Initiation of Transcription
The process that starts the transcription of an RNA molecule. It includes the assembly of the initiation complex and establishment of the start site.
Stages of Transcription.
The operator contains the code necessary to begin the process of transcribing the
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure.
Alternative splicing:
By splicing
mRNA
mRNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure in different ways, different
proteins
Proteins
Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein.
Energy Homeostasis can be created from the same
mRNA
mRNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure.
Image of a plasmid: extrachromosomal circular DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure
Image by Lecturio.Autosomal recessive Autosomal recessive Autosomal inheritance, both dominant and recessive, refers to the transmission of genes from the 22 autosomal chromosomes. Autosomal recessive diseases are only expressed when 2 copies of the recessive allele are inherited. Autosomal Recessive and Autosomal Dominant Inheritance pedigree chart
Image by Lecturio.Construction of recombinant
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure in which a foreign
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure fragment is inserted into a plasmid vector:
The gene indicated by the white color is inactivated upon insertion of the foreign
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure fragment.
The structure of a mature
eukaryotic
Eukaryotic
Eukaryotes can be single-celled or multicellular organisms and include plants, animals, fungi, and protozoa. Eukaryotic cells contain a well-organized nucleus contained by a membrane, along with other membrane-bound organelles.
Cell Types: Eukaryotic versus Prokaryotic
mRNA
mRNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure includes:
5′ cap: The linkage of 7-methylguanosine
aids
AIDS
Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions.
HIV Infection and AIDS in recognition by protein
synthesis
Synthesis
Polymerase Chain Reaction (PCR) machinery and protects from degradation by exonucleases.
UTR: untranslated regions
CDS: coding sequence, which consists of codons corresponding to specific amino
acids
Acids
Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water.
Acid-Base Balance
3’ poly-A tail: a chain of adenylate molecules, which maintains the stability of
mRNA
mRNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure as it exits the
nucleus
Nucleus
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus.
The Cell: Organelles into the
cytosol
Cytosol
A cell’s cytoskeleton is a network of intracellular protein fibers that provides structural support, anchors organelles, and aids intra- and extracellular movement.
The Cell: Cytosol and Cytoskeleton
Structure of
ribosomes
Ribosomes
Multicomponent ribonucleoprotein structures found in the cytoplasm of all cells, and in mitochondria, and plastids. They function in protein biosynthesis via genetic translation.
The Cell: Organelles:
A ribosome is a cellular particle made of
RNA
RNA
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity.
RNA Types and Structure and protein that serves as the site for protein
synthesis
Synthesis
Polymerase Chain Reaction (PCR) in the cell. The ribosome reads the sequence of the
messenger RNA
Messenger RNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure (
mRNA
mRNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure) and, using the genetic code, translates the sequence of
RNA
RNA
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity.
RNA Types and Structure
bases
Bases
Usually a hydroxide of lithium, sodium, potassium, rubidium or cesium, but also the carbonates of these metals, ammonia, and the amines.
Acid-Base Balance into a sequence of amino
acids
Acids
Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water.
Acid-Base Balance.
Central dogma of molecular biology:
Illustration of the difference between
transcription
Transcription
Transcription of genetic information is the first step in gene expression. Transcription is the process by which DNA is used as a template to make mRNA. This process is divided into 3 stages: initiation, elongation, and termination.
Stages of Transcription and
translation
Translation
Translation is the process of synthesizing a protein from a messenger RNA (mRNA) transcript. This process is divided into three primary stages: initiation, elongation, and termination. Translation is catalyzed by structures known as ribosomes, which are large complexes of proteins and ribosomal RNA (rRNA).
Stages and Regulation of Translation along with the required
enzymes
Enzymes
Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules.
Basics of Enzymes.
Secondary structure of transfer RNA Transfer RNA The small RNA molecules, 73-80 nucleotides long, that function during translation to align amino acids at the ribosomes in a sequence determined by the mRNA (messenger RNA). There are about 30 different transfer RNAs. Each recognizes a specific codon set on the mRNA through its own anticodon and as aminoacyl tRNAs, each carries a specific amino acid to the ribosome to add to the elongating peptide chains. RNA Types and Structure ( tRNA tRNA The small RNA molecules, 73-80 nucleotides long, that function during translation (translation, genetic) to align amino acids at the ribosomes in a sequence determined by the mRNA (RNA, messenger). There are about 30 different transfer rnas. Each recognizes a specific codon set on the mRNA through its own anticodon and as aminoacyl trnas (RNA, transfer, amino Acyl), each carries a specific amino acid to the ribosome to add to the elongating peptide chains. RNA Types and Structure), along with various functional sites of the tRNA tRNA The small RNA molecules, 73-80 nucleotides long, that function during translation (translation, genetic) to align amino acids at the ribosomes in a sequence determined by the mRNA (RNA, messenger). There are about 30 different transfer rnas. Each recognizes a specific codon set on the mRNA through its own anticodon and as aminoacyl trnas (RNA, transfer, amino Acyl), each carries a specific amino acid to the ribosome to add to the elongating peptide chains. RNA Types and Structure.
Image by Lecturio.Structure of a ribosome:
The large subunit is demonstrated on top with A, P, and E binding sites for charged
transfer RNAs
Transfer RNAs
The small RNA molecules, 73-80 nucleotides long, that function during translation to align amino acids at the ribosomes in a sequence determined by the mRNA (messenger RNA). There are about 30 different transfer RNAs. Each recognizes a specific codon set on the mRNA through its own anticodon and as aminoacyl tRNAs, each carries a specific amino acid to the ribosome to add to the elongating peptide chains.
Stages and Regulation of Translation; the small subunit is below the
messenger RNA
Messenger RNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure (
mRNA
mRNA
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3′ end, referred to as the poly(a) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
RNA Types and Structure).