MODULE 5. HEREDITY Flashcards
definition - alleles
alternative forms of a gene
definition - asexual reproduction
A type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only
definition - 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
definition - budding
a type of asexual reproduction in which new organism develops from an outgrowth or bud due to cell dividion at one particular site. the bulb like projection coming out from the yeast cell is called a bad
definition - carrier
a heterozygous individual not expressing a recessive trait but capable of passing it on to its offspring
definition - centromere
the replicated arms of the chromosome are held together by this structure
definition - cervix
elongate inferior end of the uterus where it connects to the vagina
definition - chromosome
structures within the nucleus made of DNA that contain all the genetic information of an organism
definition - chromatids
one of the two halves of a duplicated chromosomes
definition - cloning
a cell, cell product, or organism hat is genetically identical to the unit or individual from which it was derived.
definition - corpus iuteum
transformed follicle after ovulation that secretes progesterone
definition - 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
definition - DNA
the chemical compound that makes up genes within chromosomes and is the basic of heredity. two chains of nucleotides twist around each other to form a double helic,
definition - dominant allele
an allele that is always expressed when present, regardless of whether the organism is homozygous or heterozygous
definition - endometrium
inner lining of the uterus, part of which builds up during the secretory phase of the menstrual cycle and the sheds with menses
definition - epididymis
coiled tubular structure in which sperm start to mature and are stored until ejaculation
definition - external fertilisation
sperm fertilises egg outside female body
definition - 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
definition - internal fertilisation
sperm inserted into female body
definition - gamete
a haploid (n) sex cells in plants and animals (egg or sperm)
definition - 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).
definition - gene pool
all the genes in a population.
definition - genetics
The study of genes and inheritance patterns
definition - genotype
the genetic make-up of an individual. Eg Bb
definition - Gonadotropin-releasing hormone (GnRH)-
hormone released by the hypothalamus that regulates the production of follicle-stimulating hormone and luteinizing hormone from the pituitary gland
definition - haploid
one set of chromosomes per cell (n) found in the sex cells (23 in humans)
definition - heterozygous
possessing a pair of unlike alleles for a particular gene
definition - homozygous
possessing a pair of identical alleles for a particular gene
definition - 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.
definition - inheritance
The transmission of genetic information from a parent to a child
definition - 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.
definition - menstrual cycle
approximately 28-day cycle of changes in the uterus consisting of a menses phase, a proliferative phase, and a secretory phase
definition - mitosis
The process of cell division in body cells. Mitosis results in ‘daughter’ cells which are genetically identical to the parent cells.
definition - mutation
- A permanent, heritable change in the base sequence in a gene or a chromosome;
definition - 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
definition - Oogenesis
process by which oogonia divide by mitosis to primary oocytes, which undergo meiosis to produce the secondary oocyte and, upon fertilization, the ovum
definition - ovarian cycle
-approximately 28-day cycle of changes in the ovary consisting of a follicular phase and a luteal phase and a luteal phase
definition - ovaries
-female gonads that produce oocytes and sex steroid hormones (notably estrogen and progesterone)
definition - ovulation
-release of a secondary oocyte and associated granulosa cells from an ovary
definition - ovum
haploid female gamete resulting from completion of meiosis II at fertilization
definition - Parthenogenesis
reproduction from an ovum without fertilization, especially as a normal process in some invertebrates and lower plants
definition - penis
male organ of copulation
definition - phenotype
the physcial or chemical expression of an organism’s genes e.g. brown eyes
definition - polar body
definition - smaller cell produced during the process of meiosis in oogenesis
definition - 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
definition - recessive allele
an allele that is only expressed whn the organism is homozygous for that allele and not expressed when heterozygous (When paired with a dominant allele)
definition - semen
ejaculatory fluid composed of sperm and secretions from the seminal vesicles, prostate, and bulbourethral gland
definition - seminal vesicle
gland that produces seminal fluid, which contributes to semen
definition - selective breeding
the intentional breeeding of organisms with desirable trait in an attempt to produce offspring with similar desirable characteristics or with improved traits
definition - seminiferous tubules
tube structures within the testes where spermatogenesis occurs
definition - sexual reproduction
the production of new living organisms by combining genetic information from two individuals of different types (sexes)
definition - snps
single nucleotide polymorphisms, frequently called SNPs are the most common type of genetic variation among people. each snp represents a difference in a single nucleotide
definition - Sperm
also, spermatozoon) male gamete
definition - 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.
definition - testes
male gonads
definition - uterus
muscular hollow organ in which a fertilized egg develops into a fetus
definition - vagina
tunnel-like organ that provides access to the uterus for the insertion of semen and from the uterus
definition - zygote
diploid (2n) cell resulting from the union of two gametes in sexual reproduction
explain sexual reproduction
- Gametes are produced by parent organisms through meiosis.
- Each gamete contains half the necessary number of chromosomes
- The male gamete (sperm) fertilises the female gamete (ovum or egg) by either internal fertilisation (mammals) or external fertilisation (fish such as salmon)
- Fusion of gametes results in production of a zygote, which contains a combination of genetic material from parental organisms
advantages of sexual reproduction
- Combination of chromosomes from two organisms INCREASES IN VARIATION, which assists with survival
advantages of external reproduction
- Large number of gametes produced generally means more off spring. It is also a simpler behavioural process which does not require mating rituals
advantages of internal reproduction
- INCREASED LIKELIHOOD OF FERTILISATION as egg and sperm are in close proximity, with INCREASED PROTECTION from the environment leading to higher survival rates of offspring.