Test Your Knowledge By Answering These Genetics And Heredity Flashcards

One of the characteristics of living things is their ability to ... ? Reproduce their kind Heredity is the transfer of biological information from ... ? Parent to offspring Genetics is the branch of biology concerned with the structure, transmission, and ... ? Expression of hereditary information Genes are the ... ? Units of heredity Chromosomes (colored bodies) are the nuclear packages in which ... ? Genetic information is stored Chromosomes are composed of a tangle of darkly staining fibers called ... ? Chromotins Chromotin is composed of ... ? 60% protein, 35% DNA, and 5% RNA THe length of DNA in a single cell nucleus is estimated to be ... ? About 1 yard Each chromosome contains .... ? Thousands of genes Each gene is a unit of information which determines a specifically hereditary trait and occupies a ... ? Specific location on a chromosome Some genes are capable of transmitting their chromosomal ... ? DNA information to RNA molecules RNA molecules contain the code sequence of amino acids (the building blocks of proteins) of all proteins produced ... ? Within the organism Humans have ... ? About 75,000 genes Everyy individual in a given species possesses a specific number of chromosomes. These chromosomes occur in ... ? Virtually every cell of the body. Human body cells have 46 chromosomes. For this reason 46 is termed the ... number? Somatic The somatic number is also identified as the ... number? Diploid number (2n) The number of chromosomes present in the sex cells gametes) is 23. This is the ... number ? Haploid number (1n) The number of chromosomes between animal species varies from 2 to several hundred (The crayfish has 200 chromosomes). Many species other than man ... ? Also have 46 chromosomes Once cells reach a certain size, they must stop growing or divide. However, some cells do not normally divide. What are three of these types ? Nerve cells, cardiac muscle cells, and mature red blood cells (RBCs) The cell cycle includes all the activities of the cell during which it is ... ? Actively growing and dividing The completing of the cell cycle is termed .... ? Generation time The time to duplicate an average cell is ... ? About 24 hours The cell cycle is divided into ... ? Four phases In the M (mitosis) phase, active cell division occurs and lasts about .... ? 1-2 hours In the G1 (gap 1) phase, organelles begin to double in number and this phases lasts about... ? 8-10 hours In the S (synthesis) phase, the DNA replicates and this phase lasts about ... ? 6-8 hours In the G2 (gap 2) phase, synthesis of proteins occurs and this phases lasts about ... ? 4-6 hours Mitosis occupies approximately ... ? 5% of the total cell cycle Cell duplication involves ... ? 2 main processes Mitosis (greek for threads) is a division of the nucleus that produces an equal sharing of the chromosomes by the ... ? 2 resulting cells Cytokinesis is the division of the cytoplasm that is ... ? Coincident with mitosis The 5 phases of mitosis are ... ? Interphase, Prophase, Metaphase, Anaphase, and Telophase. What's the first phase of mitosis? Interphase What's the second phase of mitosis? Prophase What's the thirdphase of mitosis? Metaphase What's the fourth phase of mitosis? Anaphase What's the five phase of mitosis? Telophase Interphase is the normal working phase of the clel. Structures and substances such as organelles are being .... ? Synthesized and accumulated Does any cell division take place during Interphase? NO Interphase lasts about 95% of the cell cycle and the chromatin in the nucleus is "unorganized". The individual chromosomes are not .... ? Visible In prophase, the nuclear membrane and .... disappear? Nucleolus In Prophase, the chromatin begins to "organize" by coiling and folding and becoming thicker. During this process, the individual ... ? Chromosomes become visible During organization in Prophase, the chromosomes, which duplicated during the S-phase of the cell cycle are called .... ? Sister chromatids Prophase: The constructed part of the chromosome that joins the sister chromatids is called .... A centromere Prophase: Each sister chromatid has a long or short arm which extends from the centromere. The short arm is identified by the letter ... and ... ? "p" and the long arm by "q". In animal cells, the centrosome, and the two centrioles contained within it, duplicate and migrate to opposite ends (poles). Centrioles are not found in plants, although... ? The centrosome is. Prophase: As each pair of centrioles migrate to their respective poles, they pull one set of microtubule ends after them. The other set of ends are connected to the centromere halves of each sister chromatid. The spot of attachment on each centromere half is ... ? Termed the kinetochore Microscopically, the centrioles and their associated microtubules somewhat resemble starbursts and are ... ? Called asters (stars) During aster formation the chromosomes begin to organize along the ... ? Center (equator) of the cell The appearance of the 2 asters, with their microtubules radiating to the cell's equator, is known as ... ? The mitotic spindle Metaphase: The chromosomes line up along the equator of the cell with the centromeres are... The equators midline Metaphase: The mitotic spindle is complete. SPindle fibers can be seen to run from the polar centrioles to each ... ? Centromere on the equator Metaphase: The chromosomes are very distinct and are ... ? Used for genetic studied at this stage Anaphase: Sister chromatids separate at their centromeres. At this point they become ... ? Independent chromosomes. Anaphase: The separated chromosomes are pulled to opposite poles by their ... ? Attached spindle fibers Anaphase: Anaphase ends when all the chromosomes have ... ? Reached the poles Telophase: The chromosomes begin to uncoil to form ... ? Chromatin threads Telophase: The spindle ... ? Dissolves Telophase: The nucleolus ... ? Reappears Telophase: The cytoplasm divides forming the two daughter cells with the ... ? Return to interphase Cytokinesis: Cytokinesis is the division of the cytoplasm in .... ? The formation of daughter cells Cytokinesis: It begins during ... ? Telophase Cytokinesis: A cleavage furrow forms--the precursor of the cell membrane. This furrow deepens forming a contractile ring until two new cells develop ... ? Each with a new complete nucleus Cytokinesis: In plants, a cell plate forms which is ... ? Part of the cell wall Mitosis: Each replicated cell receives exactly the same chromosomes .... ? As the original cell Mitosis: The cytoplasmic organelles are evenly distributed during cytokinesis and .... ? Replicate by themselves Mitosis is ... , not sexual. Asexual The daughter cells are exact clones ... ? Of the original cell The significance of meiosis is to half the number of chromosomes during gamete formation (... ?) To maker smaller Involves .... ?. There are 2 parents. Sexual reproduction Each parent contributes a specialized sex cell (hamete). The gamete is ... ? Haploid (1n). The male gamete is the ... ? Spermatozoon (sperm) The female gemete is the ... ? Ovum (egg) Gemetogenesis is the development of gametes and occurs ... ? In the gonads Male gonads are ... ? Testes Female gonads are ... ? Ovaries During fertilization, the sperm and egg fuse to form a zygote (2n). Subsequent divisions ... ? Are diploid. The net effect of meiosis is to provide the offspring with the ... ? Genetic background of both parents The chance of combinations of these haploid gametes can result in zygote configurations (mutations) that are new for the species. The good combinations tend to .... ? Survive; and the bad do not. There are two cell divisions, but the chromosomes are only duplicated once. In mitosis there is one cell division with ... ? One duplication of chromosomes All the resulting cells are ... ? Haploid (1n) In a diploid somatic (body) cell, chromosomes ... ? Occur as pairs Each set of chromosomes is a homologous pair and each member is a ... ? Homologous chromosome or homologue or chromatid. One member of the homologous pair was inherited from the female parent; the ... ? Other was inherited from the male parent. Homologues look alike. THey have the same length, centromere position, and ... ? Banding patterns. A specific location on one homologue contains the same gene that occurs at the same location on its ... ? Homologue. First meiotic division: this phase is also called meiosis 1 or .... ? Reduction division Prior to meiosis 1, DNA replication occurs forming 2 sister chromatids for ... Each chromosome During meiosis 1, homologous chromosomes come together and line up on the equator side by side. This is termed .... ? Synapses In synapsis, the two sets (pairs) of homologous chromosomes are ... ? Described as tetrads or bivalents Crossing-over .... ? Occurs at this point Nonsister chromatid arms cross each other at various points in a .... ? Seemingly arbitrary fashion The points where the arms cross are termed chiasmata (singular: chiasma), and serve as junctures where the arm of one chromatid is exchanged for ... ? That of its sister chromatid. Because of crossing-over, the genetic instructions from a father and a mother are mixed, and the daughter cells receive .... ? Chromosomes with recombined genes. Crossing over increases genetic ... ? Variability The homologues of each tetrad separate and move to opposite poles. The centromeres remain intact, meaning ... They do not cleave Cytokinesis separates the 2 daughter cells ... ? Which are now haploid Second meiotic division. This phase is also called ... ? Meiosis II or equatorial division No replication of chromosomes .... ? Occurs at this stage The centromeres cleave (separate) releasing the 2 sister chromatids, each of which migrates ... ? To an opposite pole Cytokinesis separates the 2 sister chromatids which then ... ? Develop into haploid gametes Genetic recombination insures that offspring have a different combination of genes than their parents. This occurs as a result of 3 mechanisms. What are they? 1) Crossing-over of nonsister chromatids, 2) Independent assortment of homologous chromosomes, and 3) Fertilization results in combinations of genetically different gametes. What's the first mechanism? Crossing-over of nonsister chromatids What's the second mechanism? Independent assortment of homologous chromosomes What's the third mechanism? Fertilization results in combinations of genetically different gametes Crossing-over of ... ? Nonsister chromatids Independent assortment of ... ? Homologous chromosomes Independent assortment of homologous chromosomes: Independent alignment of tetrads at the equator during meiosis 1 causes the gametes to have ... ? Different combinations of chromosomes Comparison of meiosis to mitosis: DNA replication takes place only once during both meiosis and mitosis. However, there are two nuclear divisions during meiosis and ... ? Only one during mitosis Comparison of meiosis to mitosis: Four daughter cells (gametes) are produced by meiosis. Mitosis results in ... ? Two daughter cells Comparison of meiosis to mitosis: The four gametes formed by meiosis are hapoid. The daughter cells produced by mitosis have the same chromosomal number as ... ? The parental cell (mother cell) Comparison of meiosis to mitosis: The four daughter cells from meiosis are not genetically identical to each other or to the mother cell. The daughter cells from mitosis are genetically identical to each other and ... ? To the mother cell Meiosis occurs in the gonads during spermatogenesis and ... ? Oogenesis in humans Oogenesis occurs in the ... ? Ovaries Spermatogenesis occurs in the ... ? Testes A primary spermatocyte, with 46 chromosomes, divides by meiosis to form two secondary spermatocytes each with ... ? 23 duplicated chromosomes Secondary spermatocytes divide to produce four spermatids ... ? Also with 23 daughter chromosomes Spermatids then differentiate ... ? Into motile sperm Meiotic cell division in mals always results in ... ? Four cells that become sperm Unlike the four sperm produced from a single primary spermatocyte, only one ovum is generated from each primary oocyte. This conserves cytoplasmic materials to sustain the fertilized ovum during its week-long migration from the ovary down the Fallopian tube (where fertilization occurs) to its implantation ... ? Site within the uterus. A priamry oocyte, with 46 chromosomes, divides by meiosis to form two cells, each with ... ? 23 duplicated chromosomes One of the cells, a secondary oocyte, receives ... ? Most of the cytoplasm The other cell, a polar body (the first polar body), is ... ? Discarded and disintegrates A secondary oocyte begins meiosis II, but then temporarily stops to undergo ovulation, which means ... ? Release from the ovary The ovum enters the oviduct (Fallopian tube) where fertilization by a ... ? Sperm may occur If a sperm enters the secondary oocyte, the oocyte is activated to continue meiosis II ... ? Through to completion Another polar body (the second polar body) is ... ? Generated and discarded The result of fertilization is mature diploid cel termed a zygote which becomes the .... ? First diploid cell of a new individual Mitosis comes from the Greek word mitos which means ... ? Threads What process occurs in organisms that reproduce asexually? Mitosis What process is absolutely necessary for sexual reproduction to occur? Meiosis Eukaryote DNA molecules have large amounts of ______________ dispersed among the DNA molecules. Proteins Each chromosome contains thousands of ... ? Genes Define chromosomes: Colored bodies containing genetic information Define chromatid: Concentrated form of a chromatin Define sister chromatid: Homologous pair A chromatin is the chromosome in the ... ? Nucleus Chromatids that are attached at the Centromere are called what kind of chromatids? Sister Define centromere: Centromere is the constricted part of the chromatin that joins the sister Centromere joins duplicated DNA molecules that are called ... ? Sister chromatids Centromere position along the chromosome will not be in the exact location for every chromosome but instead ... ? Varies Microtubules attach to the kintochore of ... ? Centromeres Is a centromere permanent or temporary? Temporary Centromere is the attachment site for ... ? Spindle fibers What makes spindle fibers? Microtubules Different organisms have different number of chromosomes. Some organisms have as many as __________________ (for ex. Adder Tongue) chromosomes which indicates that more highly evolved species does NOT necessary have more chromosomes 1000 All members of the same species will have the same ______________________ of chromosomes Number The number of chromosomes remains ? throughout a life cycle Constant List in proper sequence the stages of Mitosis Prophase, Metaphase, Anaphase, Telophase (PMAT) In which stages of mitosis does each chromosome consist of two DNA molecules? Prophase and Metaphase Chromatids detach from one another and become visibly separate chromosomes during what state of mitosis? Anaphase and Telophase New nuclei are formed during what stage of mitosis? Telophase Are homologous chromosomes paired during mitosis? (yes/no) Yes and No (wth?) In .... ? ... chromosomes align at the spindle equator (think stages of mitosis) Metaphase In .... ? ... sister chromatids become individual chromosomes (think stages of mitosis) Anaphase In .... ? ... centromeres divide (think stages of mitosis) Prophase (not completely sure about this) In .... ? ... chromosomes move apart (think stages of mitosis) Anaphase In .... ? ... spindle microtubules shorten, pulling chromosomes toward the pole (think stages of mitosis) Anaphase Chromosomes are duplicated during ? of the cell’s life cycle Interphase Plants have a rigid cell wall which prevents the plant cell from being pinched in two. Instead vesicles containing remnants of themicrotubular (microtubule) spindle form a disk like structure called __ Cell-plate Chromosomes (containing DNA and carrying genes) replicate during _____ of the cell cycle Mitosis Chromosomes condense and microtubular spindle develops during this phase of mitosis ... ? Prophase During what stage of mitosis does homologous pairs of chromosomes line up on the equatorial plate? ____ Metaphase At this stage of mitosis sister chromatids joined at their centromeres are attached to spindle fibers. ________ Metaphase During this phase of mitosis the centromeres break apart as the separated sister chromatids begin to move to opposite poles. ____ ? Anaphase Cytokinesis occurs at the end of ________ Telophase New daughter nuclear membranes form during this phase of mitosis. _____ Telophase Spindle fibers are about 25nm in diameter and are formed from ______ Microtubules Physical separation of the cytoplasm occurs during ________ Cytokinesis _____ move to opposite poles and form spindle fibers Centrioles . Two sister chromatids are joined at the ___________ Centromere Chromosome name changes during its life cycle from chromatin to chromatid. What name does it have when it is half of a chromosome in prophase? Sister-chromatid Sexual reproduction results in new combinations of genetic _____ Traits If meiosis did NOT occur in sexually reproducing organisms, the chromosome number would ________________ in each generation Increase Through ________________________, offspring are provided with new gene combinations Meiosis Through meiosis, parental DNA is divided and distributed to forming gametes. This results in diploid chromosome number to be reduced to _________________ number Haploid number Meiosis allows alternate forms of genes to be _____ This enables offspring to have a new gene combination Shuffled Different, or alternative, forms of the same gene are called ______ Alleles In meiosis, each gamete receives one member of each pair of homologous chromosomes and ______________ are formed that are haploid Gametes Homologous chromosomes are in pairs, one chromosome from each pair comes from the father and one from the __________ Mother Homologous chromosomes may exchange parts during ____________ of meiosis Crossing-over (prophase1 ) Crossing over alters the composition of chromosomes and results in new combinations of ___________ that eventually are channeled into the daughter cells Alleles Crossing over is one of the most important events in meiosis because it produces new arrays of ___________ on chromosomes. Alleles If a diploid organism has a genome consisting of 3 chromosomes, it can produce ________ different combinations of maternal and paternal chromosomes (disregarding crossing over 8 The haploid number for human chromosomes is ____. The diploid number is _____. Altogether there are ______ pairs of chromosomes. Human gametes end up with _______ of each type of 23 chromosomes 23,46,92 spermatogonium is ... ? Diploid primary spermatocyt ... ? Diploid secondary spermatocyte ... ? Haploid spermatids ... ? Haploid oogonium ... ? Diploid primary oocyte ... ? Diploid secondary oocyt ... ? Haploid ovum ... ? Haploid polar bodies ... ? Haploid Polar bodies do ________________ develop into a gamete Not A pine tree is called a sporophyte because it produces spores by (mitosis or meiosis?) Meiosis