m bilogy

1. Molecular biology
Molecular biology is the branch of biology that studies the
molecular basis of biological activity.
Living things are made of chemicals just as non-living things are, so a
molecular biologist studies how molecules interact with one another in
living organisms to perform the functions of life

2. Nucleic acids
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are large biomolecules that play essential roles in all cells and
viruses.
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A major function of nucleic acids involves the storage and expression
of genomic information. Deoxyribonucleic acid, or DNA, encodes the
information cells need to make proteins

3. Types of Nucleic acids
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macromolecules made out of units called nucleotides,
come in two naturally occurring varieties:
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1- deoxyribonucleic acid (DNA)
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2- ribonucleic acid (RNA)

4. types of DNA
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The three types of DNA are:
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A- DNA: It is right-handed DNA that contains a double helix.
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B- DNA: This DNA is a right-handed helix one and is a
common one.
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Z- DNA is a left-handed double helix DNA with a zigzag pattern.
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5. types of RNA
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The three types of DNA are:
1- messenger RNA (mRNA),
2- transfer RNA (tRNA)
3- ribosomal RNA (rRNA).
rRNA forms ribosomes, which are essential in protein synthesis

6. Chromosomes
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are thread-like structures located inside the nucleus of animal
and plant cells.
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Each chromosome is made of protein and a single molecule of
deoxyribonucleic acid (DNA). Passed from parents to offspring,
DNA contains the specific instructions that make each type of
living creature unique

7. Site of chromosome
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In the nucleus of each cell, the DNA molecule is packaged into
thread-like structures called chromosomes. Each chromosome
is made up of DNA tightly coiled many times around proteins
called histones that support its structure

8. A plasmid
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A plasmid is a small circular DNA molecule found in
bacteria and some other microscopic organisms. Plasmids
are physically separate from chromosomal DNA and replicate
independently.

9. transposon
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A transposable element (TE, transposon, or jumping gene)
is a nucleic acid sequence in DNA that can change its position
within a genome, sometimes creating or
reversing mutations and altering the cell's genetic identity
and genome size.

10. Chromatin
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Chromatin refers to a mixture of DNA and proteins that
form the chromosomes found in the cells of humans and
other higher organisms.
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Many of the proteins — namely, histones — package the
massive amount of DNA in a genome into a highly compact
form that can fit in the cell nucleus

11. A nucleosome
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is the basic repeating subunit of chromatin packaged
inside the cell's nucleus.
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In humans, about six feet of DNA must be packaged into a
nucleus with a diameter less than a human hair, and
nucleosomes play a key role in that process.

12. Gene
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The gene is considered the basic unit of inheritance.
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Genes are passed from parents to offspring and contain the
information needed to specify physical and biological traits.
Most genes code for specific proteins, or segments of proteins,
which have differing functions within the body

13. Genome
The genome is the entire set of DNA instructions found in a cell.
In humans, the genome consists of 23 pairs of chromosomes
located in the cell's nucleus, as well as a small chromosome in
the cell's mitochondria. A genome contains all the information
needed for an individual to develop and function

14. Transcriptome
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The transcriptome is the set of all RNA transcripts,
including coding and non-coding, in an individual or a
population of cells.
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The term can also sometimes be used to refer to all RNAs, or
just mRNA, depending on the particular experiment. The
term transcriptome is a portmanteau of the
words transcript and genome; it is associated with the process
of transcript production during the biological process
of transcription.

15. EXON
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a polynucleotide sequence in a nucleic acid that codes information for
protein synthesis and that is copied and spliced together with other
such sequences to form messenger RNA

16. INTRON
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An intron is any nucleotide sequence within a gene that is
not expressed or operative in the final RNA product. The
word intron is derived from the term intragenic region, i.e., a
region inside a gene.[1] The term intron refers to both the DNA
sequence within a gene and the corresponding RNA sequence
in RNA transcripts.[2] The non-intron sequences that become
joined by this RNA processing to form the mature RNA are
called exons.

17. A nucleotide
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A nucleotide is the basic building block of nucleic acids
(RNA and DNA). A nucleotide consists of a sugar molecule
(either ribose in RNA or deoxyribose in DNA) attached to a
phosphate group and a nitrogen-containing base. The bases
used in DNA are adenine (A), cytosine (C), guanine (G) and
thymine (T

18. nucleoside,
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a structural subunit of nucleic acids, the heredity-
controlling components of all living cells, consisting of a
molecule of sugar linked to a nitrogen-containing organic ring
compound.

19. central dogma
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In molecular biology, central dogma illustrates the flow of
genetic information from DNA to RNA to protein. It is defined as
a process in which the information in DNA is converted into a
functional product.
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It is suggested that the information present in a DNA is essential
to make up all proteins and RNA acts as a messenger that
carries information through the ribosomes.

20. DNA replication
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is the process by which the genome's DNA is copied in
cells. Before a cell divides, it must first copy (or replicate) its
entire genome so that each resulting daughter cell ends up with
its own complete genome

21. Backbone of DNA
A structural component of DNA that consists of 5-
deoxyribose sugars and phosphate groups involved in carrying the
genetic code.

23. semi-conservative
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This process is known as semi-conservative replication
because two copies of the original DNA molecule are
produced, each copy conserving (replicating) the information
from one half of the original DNA molecule. Each copy contains
one original strand and one newly synthesized strand

24. Primers
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are short stretches of DNA that target unique sequences
and help identify a unique part of genome — let's say, a
gene. Primers are usually 18 to 25 nucleotides long. They can
be synthesized in a special lab, and are used in many different
ways

25. probe
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is a single-stranded sequence of DNA or RNA used to search for its
complementary sequence in a sample genome. The probe is placed into
is placed into contact with the sample under conditions that allow the probe
sequence to hybridize with its complementary sequence. The probe is labeled
with a radioactive or chemical tag that allows its binding to be visualized. In a
similar way, labeled antibodies are used to probe a sample for the presence of
a specific protein.

26. RNA Transcription
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is the process of copying a segment of DNA into RNA. The
segments of DNA transcribed into RNA molecules that can
encode proteins produce messenger RNA (mRNA). Other
segments of DNA are transcribed into RNA molecules
called non-coding RNAs (ncRNAs).

27. translation
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In translation, messenger RNA (mRNA) is decoded in a
ribosome, outside the nucleus, to produce a specific amino
acid chain, or polypeptide. The polypeptide later folds into an
active protein and performs its functions in the cell

28. Genetic code
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is the set of rules used by living cells to translate information
encoded within genetic material (DNA or RNA sequences of
nucleotide triplets, or codons) into proteins.

29. The degeneracy of the genetic code
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refers to the fact that most amino acids are specified by
more than one codon.
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The exceptions are methionine (AUG) and tryptophan (UGG

30. Gene expression
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is the process by which the information encoded in a gene
is turned into a function.
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This mostly occurs via the transcription of RNA molecules that
code for proteins or non-coding RNA molecules that serve other
functions

31. phenotype
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The term "phenotype" refers to the observable physical
properties of an organism;
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these include the organism's appearance, development, and
behavior. An organism's phenotype is determined by its
genotype, which is the set of genes the organism carries, as
well as by environmental influences upon these genes

32. genotype
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In a broad sense, the term "genotype" refers to the genetic
makeup of an organism; in other words, it describes an
organism's complete set of genes. In a more narrow sense, the
term can be used to refer to the alleles, or variant forms of a
gene, that are carried by an organism

33. Allele
is one of two or more versions of DNA sequence (a single
base or a segment of bases) at a given genomic location.
An individual inherits two alleles, one from each parent, for
any given genomic location where such variation exists. If
the two alleles are the same, the individual is homozygous
for that allele. If the alleles are different, the individual is
heterozygous.
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34. Locus
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the set of all points whose location is determined by stated conditions
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the position in a chromosome of a particular gene or allele

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