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69 Cards in this Set
- Front
- Back
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organs
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large anatomical structures made from several tissues working together toward a common goal
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mitosis
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a type of nuclear division that is characterized by complex chromosomal movement and the exact duplication of chromosomes; occurs in somatic cells
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meiosis
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a process of cell division whereby each daughter cell receives only one set of chromosomes; the formation of gametes
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binary fission
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asexual reproduction; in this process, the parent organism splits into two equal daughter cells. Occurs in prokaryotes, algae, and bacteria.
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Conjugation
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a mechanism used by bacteria to move genes between cells by exchanging a circular extrachromosomal DNA with each other.
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transduction
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a process in which viruses that infect bacteria can accidentally carry bacterial genes with them into a new cell that they infect. These processes can introduce new genes into bacteria, but do not involve the union of gametes from two parents that is involved in sexual production.
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the cell cycle
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the growth and division of cells to make new cells occurs in what is known as the cell cycle. The cell cycle is a highly regulated process, linked to the growth and differentiation of tissues.
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Stage G1
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G1 is characterized by intense biochemical and biosynthetic activity and growth. The cell doubles in size, and new organelles such as mitochondria, ribosomes, and centrioles are produced.
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Stage S
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synthesis of DNA; chromosomal replication; sister chromatids.
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Sister chromatids
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one of two strands that constitute a chromosome; chromatids are held together by the centromere.
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telomeres
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the ends of chromosomes
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Stage G2
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the cell prepares for mitosis, making any of the components still needed to complete cell division.
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Stage M
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(mitosis and cytokinesis) Mitosis is the stage in which the cell divides to create two similar but smaller daughter cells.
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prophase
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chromosomes condense, spindles
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metaphase
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chromosomes align
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anaphase
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sister chromatids separate
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telophase
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new nuclear membranes form
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cytokinesis
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division of the cell. The cytoplasm and all the organelles of the cell are diviides as the plasma membrane pinches inward and seals off to complete the separation of the two newly formed daughter cells from each other.
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asexual reproduction
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any method of producing new organisms in which fusion of nuclei from two individuals (fertilization) does not take place.
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sexual reproduction
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the fusion of nuclei from two parent individuals to create a new individual.
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budding
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a process of asexual reproduction in which the offspring develop from an outgrowth of the plant of animal. Examples include yeast and hydra (unicellular and multicellular organisms). Unlike binary fission, budding involves an unequal division of the cytoplasm and asymmetrical daughter cells.
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parthenogenesis
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a form of asexual reproduction in which the egg develops in the absence of sperm (e.g. queen bees)
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regeneration
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the ability of certain animals to regrow missing body parts. For examples, the planaria, the earthworm, the lobster, and the sea star
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meiosis
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a process of cell division whereby each daughter cell receives only one set of chromosomes; the formation of gametes
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haploid cell
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describes cells (gametes) that have half the chromosome number typical of the species (n chromosome number)
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gametes
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a sex or reproductive cell that must fuse with another of the opposite type to form a zygote, which subsequently develops into a new organism.
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zygote
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a cell resulting from the fusion of gametes
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gonads
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the reproductive organ that produces sex cells (e.g., ovary, testes)
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testes
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the male gonads that produce sperm and male hormones
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spermatozoa
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male gametes
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ovaries
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the female gonad in animals; the base of the pistil in plants
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ova
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eggs produced by the ovaries
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germ cell
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a reproductive cell
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somatic cells
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any cell that is not a reproductive cell
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scrotum
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the human male produces sperm in the testes, gonads located in an outpocketing of the abdominal wall called the scrotum.
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seminiferous tubules
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structures in the testes that produce sperm and semen
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sertoli cells
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they are in the seminiferous tubules and support the sperm
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leydig cells
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make the testosterone that supports male secondary sex characteristics.
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testosterone
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male hormones (support male secondary sex characteristics)
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vas deferens
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carry sperm to the urethra that passes through the penis
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prostrate gland
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along with the seminal vesicles, add secretions to the sperm that carries and provides nutrients for the sperm as part of semen.
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seminal vesicles
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along with the prostrate gland, add secretions to the sperm that carries and provides nutrients for the sperm as part of semen.
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androgens
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testosterone and other steroid hormones. Induce secondary sexual characteristics of the male, such as facial and pubic hair, changes in body shape, and deepening voice changes.
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spermatogenesis
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produces four mature sperm; each sperm has an X or Y chromosome and does not donate mitochondria to the embryo; is a continuous process; produces fresh sperm daily
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spermatocytes
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in the testes, diploid germ cells divide mitotically to create primary spermatocytes, which continuously undergo meiosis to form four haploid spermatids from each primary spermatocyte.
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spermatids
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must mature further to develop the head with DNA and the tail for motility that are found in mature sperm.
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acrosome
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a specialized sac at the tip of the sperm full of enzymes that allow the sperm to break through the protective
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fertilization
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the fusion of sperm and egg to produce a zygote
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dizygotic twins
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result of multiple fertilization
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monozygotic twins
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result of separation of identical cells during the early stages of cleavage.
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external fertilization
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occurs in vertebrates that reproduce in water including most fish and amphibians. Eggs are laid in water and sperm are deposited near them in the water. Chances of fertilization are reduced. Decreased chance of survival for the young.
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morula
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the solid ball of cells that results from cleavage of an egg; a solid blastula that precedes the blastula stage
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blastula
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a stage of embryonic development in which the embryo consists of a hollow ball of cells
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blastocoel
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the central cavity of the blastula filled with fluid secreted by the cells.
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gastrula
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a stage of embryonic development characterized by the differentiation of the cells into the ectoderm and endoderm germ layers and by the formation of the archenteron; can be two-layer or three-layer
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ectoderm
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the outermost embryonic germ layer that gives rise to the epidermis and the nervous system
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endoderm
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the innermost embryonic germ layer that gives rise to the lining of the alimentary canal and to the digestive and respiratory organs
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mesoderm
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the primary germ layer, developed from the lip of the blastopore, that gives rise to the skeleton, the circulatory system, and many organs and tissues between the epidermis and the epithelium
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gastrulation
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the formation and rearrangement of the three germ layers
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chorion
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lines the inside of the egg shell
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allantois
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a saclike structure developed from the digestive tract (another embryonic membrane). It carries out functions like respiration and excretion, particularly the exchange of gases with the external environment. The allantois layer has many blood vessels to take in O2 and give off CO2, water, salt, and nitrogenous wastes.
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amnion
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a third embryonic membrane, which encloses the amniotic fluid. Amniotic fluid provides a watery environment for the embryo to develop in, and provides protection against shock.
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yolk sac
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encloses the yolk. Blood vessels in the yolk sac transfer food to the developing embryo.
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placenta
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a structure formed by the wall of uterus and the chorion of embryo; serves as the area in which the embryo obtains nutrition from the parent
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umbilical cord
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attaches the embryo to the placenta and is composed completely of tissues of embryonic, not maternal, origin. This cord contains the umbilical artery and vein.
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maturation
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the development of the embryo to the adult. Cell division; differentiation; increase in size; development of a distinctive adult shape
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mechanical breakdown
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breaking food into small pieces
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chemical breakdown
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breaking down biopolymers with enzymes into small pieces. Enzymatic hydrolysis.
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absorption
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taking nutrients up into cells.
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