Download Glossary Algae: Unicellular or simple multicellular photosynthetic

Glossary
Algae:
Unicellular or simple multicellular photosynthetic
organisms lacking multicellular sex organs.
Amino acid: Monomeric building blocks of proteins,
consisting of a carbon atom bound to a carboxyl
group, an amino group, a hydrogen atom, and a
distinctive side chain.
Angiosperms: Angiosperms are a group of vascular plants
whose seeds are enclosed by a ripened ovary or
fruit. The flowering plants or angiosperms are the
most diverse group of land plants.
ATP synthase: ATP synthase is a general term for an
enzyme that can synthesize adenosine triphosphate
(ATP) from adenosine diphosphate (ADP) and
inorganic phosphate by using a form of energy, such
as the energy from a proton gradient.
Bacteriophage: A virus that infects bacterial cell; also called
a phage.
Binary fission: Asexual reproduction by division of one cell
or body into two equal or nearly equal parts.
Cell division: Separation of a cell in to two daughter cells.
In eukaryotic cells it entails division of the nucleus
(mitosis) closely followed by the division of the
cytoplasm (cytokinesis).
Cell: The cell is the functional basic unit of life.
Chlorophyll: The major photosynthetic pigment of plant
cells.
Chloroplast:
Chlorophyll-containing
plastid
in
which
photosynthesis occurs.
Chromatin: The complex of DNA and proteins of which
eukaryotic chromosomes are composed; chromatin
is highly uncoiled and diffuse in interphase nuclei,
condensing to form the visible chromosomes in
prophase.
Chromosome: (Gr. chroma, colour + soma, body). The
structure by which hereditary information is
physically transmitted from one generation to the
next; in a bacterium, the chromosome consists of
a single nacked circle of DNA; in eukaryotes, each
chromosome consists of a single linear DNA
molecule and associated proteins.
Codon bias: Refers to the fact that not all codons are used
equally frequently in the genes of a particular
organism.
Cytochrome: Any of several iron-containing protein
pigments that serve as electron carriers in transport
chains of photosynthesis and cellular respiration.
Cytoplasm: The substance of a cell between cell membrane
and nucleus.
Dalton: Unit of molecular weight; one dalton equals onetwelfith the mass of carbon 12.
Deletion: In genetics, a deletion (also called gene deletion,
deficiency, or deletion mutation) is a mutation in
which a part of a chromosome or a sequence of DNA
is missing. Deletion is the loss of genetic material.
Deoxyribonucleic acid (DNA): The genetic material of all
organisms; composed of two complementary
chains of nucleotides wound in a double helix.
Differentiation: Process by which a cell undergoes a
change to an overtly specialized cell type.
Dimer: A protein or other structure that comprises two
subunits.
Endoplasmic reticulum: It is a well-developed electronmicroscopic network of interconnected cisternae,
tubules and vesicles present throughout the
cytoplasm in cells of eukaryotes.
Endosymbiont theory: A theory that states that the
mitochondria and chloroplasts of eukaryotic cells are
derived from symbiotic prokaryotes.
Enzyme: A protein that acts as a biological catalyst.
Eukaryote: (Gr. eu, good+ karyon, kernel). A cell
characterized by membrane- bound organelles,
mostly notably the nucleus, and one that possesses
chromosomes where DNA is associated with
proteins; an organism composed of such cells.
Fatty acids: Long hydrocarbon chains usually linked to a
carboxyl group (COO-).
Gene: (Gr. genos, birth, race). The basic unit of heredity; a
sequence of DNA nucleotides on a chromosome
that encodes a protein, tRNA, or rRNA molecule, or
regulates the transcription of such a sequence.
Genetic engineering: Array of techniques that facilitate the
manipulation and duplication of pieces of DNA for
industrial, medical and research purposes.
Genome: The genome is the entirety of an organism's
hereditary information. It includes both the genes
and the non-coding sequences of the DNA.
Genomics: The study of genomes as opposed to individual
genes.
Haploid: (Gr. haploos, single+ploion, vessel). Having only
one set of chromosomes (n), in contrast to diploid
(2n).
Homozygous: A diploid nucleus that contains two identical
alleles for a particular gene.
Intron: Portion of mRNA as transcribed from eukaryotic DNA
that is removed by enzymes before the mature
mRNA is translated in to protein.
Inversion: Type of mutation in which a segment of
chromosome is inverted.
Inverted repeat: Two identical nucleotide sequences
repeated in opposite orientations in a DNA molecule.
Kilobase: Unit of length equal to 1000 base pairs in
deoxyribonucleic acid or 1000 nitrogenous bases in
ribonucleic acid. Abbreviated kb; kbp.
Lipid: (Gr. lipos, fat). A nonpolar hydrophobic organic
molecule that is insoluble in water, but that dissolves
readily in nonpolar organic solvents; includes fats,
oils, waxes, steroids, phospholipids, and carotenoids.
Lysosome: A membrane-bound cytoplasmic organelle
containing a rich variety of hydrolytic enzymes
capable of breaking down most types of biological
molecules.
Matrix: A general term describing the interiors of organelles
where the medium is assumed to be relatively
unstructured.
Messenger RNA (mRNA): The RNA transcribed from
structural genes; RNA molecules complementary to a
portion of one strand of DNA, which are translated
by the ribosomes to form protein.
Micron: A metric unit of length equal to one millionth of a
meter.
Mitochondria: A cytoplasmic organelle bounded by two
membranes, the inner one of which is infolded
(cristae) and contains the components of electron
transport and oxidative phosphorylation; the matrix
contains the enzymes of the Kreb’s cycle.
Mutagen: A chemical or physical agent that can cause a
mutation in a DNA molecule.
Mutagenesis: Treatment of a group of cells or organisms
with a mutagen as a means of inducing mutations.
Mutation: An alteration in the nucleotide sequence of a DNA
molecule.
NADPH dehydrogenase: In enzymology, a NADPH
dehydrogenase is an enzyme that catalyzes the
chemical reaction: NADPH + H+ + acceptor NADP+
+ reduced acceptor. The 3 substrates of this enzyme
are NADPH, H+, and acceptor, whereas its two
products are NADP+ and reduced acceptor.
Nuclear Envelope: Flattened sac or double membrane
surrounding the nucleoplasm and genetic material.
Nucleotide: A single unit of nucleic acid, composed of a
phosphate, a five-carbon sugar (either ribose or
deoxyribose), and a purine or a pyrimidine.
Nucleus: The chromosome-containing compartment of the
eukaryotic cell, bounded by a double membrane
system.
Open reading frame (ORF): A series of codons starting
with an initiation codon and ending with a
termination codon. The part of a protein-coding gene
that is translated into protein.
Organelle: (Gr. organelle, a little tool). Specialized part of a
cell, literally a small cytoplasmic organ.
Photosynthesis: Process of trapping the energy of sunlight,
transforming it in to chemical energy, and storing it
in the chemical bonds of carbohydrates.
Photosystem I: A protein complex in the thyllakoid
membrane that uses energy absorbed from sunlight
to synthesize NADPH.
Photosystem II: A protein complex in the thyllakoid
membrane that uses energy absorbed from sunlight
to synthesize ATP.
Phylogeny: A classification scheme that indicates the
evolutionary relationships between organisms, often
presented in chart form as a phylogenetic tree.
Pigment: A molecule that absorbs light.
Plasmagene: A selr-replicating, cytoplasmically located
gene.
Plasmid: A small fragment of extrachromosomal DNA,
usually circular, that replicates independently of
the main chromosome, although it may have been
derived from it.
Plastid: An organelle in the cells of photosynthetic
eukaryotes that is the site of photosynthesis and, in
plants and green algae, of starch storage.
Polysomes: A string of aggregated ribosomes, connected by
messenger RNA.
Prokaryote (Gr. pro-before+karyon-kernel): A bacterium; a
cell lacking a membrane-bounded nucleus or
membrane-bounded organelles.
Protein: (Gr. proteios, primary). A chain of amino acids
joined by peptide bonds.
Purine: The larger of the two general kinds of nucleotide
base found in DNA and RNA; a nitrogenous base with
a double ring-structure, such as adenine or guanine.
Pyrimidine: The smaller of two general kinds of nucleotide
base found in DNA and RNA; a nitrogenous base with
a single-ring structure, such as cytosine, thymine, or
uracil.
Recombination: Exchange of genetic material between
homologue chromosomes.
Ribonucleic acid (RNA): A class of nucleic acids
characterized by the presence of the sugar ribose
and the pyrimidine uracil; includes mRNA, tRNA
and rRNA.
ribosomal RNA (rRNA): A class of RNA molecules found
together with characteristic proteins, in ribosomes;
transcribed from the DNA of the nucleolus.
Ribosome: Complex ribonucleoprotein particle that in
conjunction with messenger and transfer RNA and
several other factors, constitute the site of protein
synthesis in prokaryotic and eukaryotic cells and in
chloroplast and mitochondria.
RNA editing: A process by which nucleotides not coded by a
gene are introduced at specific positions in an RNA
molecule after transcription.
RNA polymerase: An enzyme that catalyzes the assembly
of an mRNA molecule, the sequence of which is
complementary to a DNA molecule used as template.
RuBisCO:
Ribulose-1,5-bisphosphate
carboxylase
oxygenase, most commonly known by the shorter
name RuBisCO, is an enzyme involved in the Calvin
cycle that catalyzes the first major step of carbon
fixation, a process by which the atoms of
atmospheric carbon dioxide are made available to
organisms in the form of energy-rich molecules such
as
glucose.
RuBisCO
catalyzes
either
the
carboxylation or the oxygenation of ribulose-1,5bisphosphate (also known as RuBP) with carbon
dioxide or oxygen.
Segregation: The separation of homologous chromosomes,
or members of allele pairs, into different gametes
during meiosis.
Spermatozoa: The male gamete, usually smaller than the
female gamete, and usually motile.
Stop codon: In the genetic code, a stop codon (or
termination codon) is a nucleotide triplet within
messenger RNA that signals a termination of
translation.
Stroma: The compartment of chloroplasts that lies between
the envelope and the thyllakoid membrane.
Test cross: A genetic cross between a double heterozygote
and a double homozygote.
Transcription: The enzyme-catalyzed assembly of an RNA
molecule complementary to a strand of DNA.
transfer RNA: A class of small RNAs with two functional
sites; at one site an “activating enzyme” adds a
specific amino acid, while the other site carries the
nucleotide triplet (anticodon) specific for that amino
acid.
Translation: The assembly of a protein on the ribosomes,
using mRNA to specify the order of amino acids.
Translocation: The movement of a ribosome along
an mRNA molecule during translation.
Translocation: Type of mutation in which a portion of one
chromosome is broken off and attached to another.
Disomic: The condition in which there are two sets of similar
(homologous) chromosomes, such that there are two
alleles for each gene locus.
Haploid: The condition in which there is only a single
chromosome; or set of chromosomes, such that all
loci are represented by only a single allele.
Phylogenetics: Reconstruction of the evolutionary
relationship between sequences using any of a variety of
interference methods.