Glossary Flashcards
Alleles
alternative forms of a gene.
Asexual reproduction
a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only
Binary fission
(“division in half”) is a kind of asexual reproduction. It is the most common form of reproduction in prokaryotes such as bacteria. It occurs in some single-celled Eukaryotes like the Amoeba and the Paramoecium.
Budding
a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The bulb like projection coming out from the yeast cell is called a bud.
Carrier
a heterozygous individual not expressing a recessive trait but capable of passing it on to its offspring
Centromere
The replicated arms of the chromosome are held together by this structure.
Cervix
elongate inferior end of the uterus where it connects to the vagina
Chromosome
structures within the nucleus made of DNA that contain all the genetic information of an organism
Chromatids
one of the two halves of a duplicated chromosome
Cloning
a cell, cell product, or organism that is genetically identical to the unit or individual from which it was derived.
Corpus luteum
transformed follicle after ovulation that secretes progesterone
Diploid
Having two sets of chromosomes or double the haploid number of chromosomes. with One member of each chromosome pair comes from the ovum and one from the sperm.
DNA (deoxyribonucleic acid)
The chemical compound that makes up genes within chromosomes and is the basic material of heredity. Two chains of nucleotides twist around each other to form a double helix.
Dominant allele
an allele that is always expressed when present, regardless of whether the organism is homozygous or heterozygous for that gene.
Endometrium
inner lining of the uterus, part of which builds up during the secretory phase of the menstrual cycle and then sheds with menses
Epididymis
(plural = epididymides) coiled tubular structure in which sperm start to mature and are stored until ejaculation
External fertilisation
sperm fertilises egg outside female body.
Fragmentation
a form of asexual reproduction in which an organism is split into fragments. Each of these fragments develop into matured, fully grown individuals that are identical to their parents.
Internal fertilisation
sperm inserted into female body
Gamete
a haploid (n) sex cell in plants and animals (egg or sperm)
Gene
a discrete unit of hereditary information that usually specifies a protein; a region of DNA (locus) located on a chromosome that specifies a trait (characteristic).
Gene pool
all the genes in a population.
Genetics
The study of genes and inheritance patterns
Genotype
the genetic make-up of an individual. Eg Bb
Gonadotropin-releasing hormone (GnRH)
hormone released by the hypothalamus that regulates the production of follicle-stimulating hormone and luteinizing hormone from the pituitary gland
Haploid
one set of chromosomes per cell (n) found in the sex cells (23 in humans)
Heterozygous
possessing a pair of unlike alleles for a particular gene.
Homozygous
possessing a pair of identical alleles for a particular gene.
Homologous chromosomes
chromosomes that are similar in shape and form and the genes they consist of. One set comes from the father and the other from the mother.
Inheritance
The transmission of genetic information from a parent to a child
Meiosis
The special cell division which only takes place in the sex cells of females and males, resulting in egg and sperm cells that contain 23 chromosomes (the haploid number). ‘Daughter’ cells not identical to parent cells.
Menstrual cycle
approximately 28-day cycle of changes in the uterus consisting of a menses phase, a proliferative phase, and a secretory phase
Mitosis
The process of cell division in body cells. Mitosis results in ‘daughter’ cells which are genetically identical to the parent cells.
Mutation
A permanent, heritable change in the base sequence in a gene or a chromosome
Oocyte
cell that results from the division of the oogonium and undergoes meiosis I at the LH surge and meiosis II at fertilization to become a haploid ovum
Oogenesis
process by which oogonia divide by mitosis to primary oocytes, which undergo meiosis to produce the secondary oocyte and, upon fertilization, the ovum
Ovarian cycle
approximately 28-day cycle of changes in the ovary consisting of a follicular phase and a luteal phase
Ovaries
female gonads that produce oocytes and sex steroid hormones (notably estrogen and progesterone)
Ovulation
release of a secondary oocyte and associated granulosa cells from an ovary
Parthenogenesis
reproduction from an ovum without fertilization, especially as a normal process in some invertebrates and lower plants
Penis
male organ of copulation
Phenotype
the physical or chemical expression of an organism’s genes. Eg Brown eyes
Polar body
smaller cell produced during the process of meiosis in oogenesis
Prostate gland
doughnut-shaped gland at the base of the bladder surrounding the urethra and contributing fluid to semen during ejaculation, scrotum external pouch of skin and muscle that houses the testes
Recessive allele
an allele that is only expressed when the organism is homozygous for that allele and not expressed when heterozygous (when paired with a dominant allele).
Semen
ejaculatory fluid composed of sperm and secretions from the seminal vesicles, prostate, and bulbourethral glands
Seminal vesicle
gland that produces seminal fluid, which contributes to semen
Selective Breeding
The intentional breeding of organisms with desirable trait in an attempt to produce offspring with similar desirable characteristics or with improved traits.
Seminiferous tubules
tube structures within the testes where spermatogenesis occurs
Sexual reproduction
the production of new living organisms by combining genetic information from two individuals of different types (sexes).
SNPS
Single nucleotide polymorphisms, frequently called SNPs (pronounced “snips”), are the most common type of genetic variation among people. Each SNP represents a difference in a single nucleotide
Sperm
(also, spermatozoon) male gamete
Spores
a reproductive cell capable of developing into a new individual without fusion with another reproductive cell. Spores are produced by bacteria, fungi, algae, and plants.
Testes
(singular = testis) male gonads
Uterus
muscular hollow organ in which a fertilized egg develops into a fetus
Vagina
tunnel-like organ that provides access to the uterus for the insertion of semen and from the uterus
Zygote
diploid (2n) cell resulting from the union of two gametes in sexual reproduction
