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Human Biology and Heredity Quiz 7 - Final Exam Flashcards

Dr. Westholm's Human Biology and Heredity class at The College of St. Scholastica

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1111358458diploid- 23 pairs, 46 total1
1111358459haploid- 1 copy of each duplicated chromosome2
1111358460autosome- two of each chromosome3
1111358461sex chromosome- on the 23rd chromosome4
1111358462homologous chromosome- pairs of corresponding chromosomes - contains same genes (not necessarily same sequence)5
1111358463how is DNA organized?- in structures called chromosomes6
1111358464what structures are included in the organization of DNA?- proteins7
1111358465interphase- longest stage - G1, S, and G2 phases8
1111358466G1 phase- cell growth9
1111358467S phase- DNA copied and its chromosomes are duplicated10
1111358468G2 phase- preparation for mitosis11
1111358469Mitosis- chromosomes are sorted into two sets and the cytoplasm divides12
1111358470mitosis: prophase- chromosomes duplicated - spindle fibers connect to centromere13
1111358471cytokinesis- division of cytoplasm of a dividing cell14
1111358472how does cytokinesis occur?- former spindle equator forms a ring of microfilaments attached to the plasma membrane and it contracts15
1111358473spermatogenesis- formation of sperm through meiosis16
1111358474oogenesis- formation of eggs (oogonium) through meiosis17
1111358475compare and contrast mitosis and meiosis- meiosis is the first step in the formation of gametes (sperm and eggs) for sexual reproduction - mitosis is the splitting of diploid germ cells to haploid nuclei (somatic cells)18
1111358476crossing over- occurs in meiosis - homologous chromosomes exchange corresponding segments19
1111358477what is the result of crossing over?- variations in inherited traits20
1111358478the consequence of germ cells that performed mitosis instead of meiosis?...21
1111358479gene- humans have about 21,500 - chemical instructions for building proteins22
1111358480allele- each version of a gene23
1111358481gene locus- specific location on a chromosome to find a gene24
1111358482dominent- presence of a dominant trait will mask recessive - example: widow's peak25
1111358483recessive- need two copies of a recessive allele for expression of trait - hitchhiker's thumb26
1111358484homozygous- identical alleles27
1111358485heterozygous- different alleles28
1111358486genotype- inherited alleles - example: AA, Aa, aa29
1111358487phenotype- observable functional or physical traits - height, eye color, etc.30
1111358488intro to genetics #2look on study guide31
1111358489independent assortment- occurs during meiosis - a given chromosome and its genes move randomly into gametes32
1111358490intro to genetics #4look on study guide33
1111358491co-dominence- heterozygous for a trait, but both alleles are expressed34
1111358492how does co-dominence apply to blood typing?- alleles for blood type determine presence or absence of polysaccharides on surface of red blood cells35
1111358493polygenic traits- combined expression of several genes - examples: height, disease susceptibility, hair color, eye color36
1111358494continuous variation- populations show a range of continuous differences - most evident in traits that can be measured (ex. height)37
1111358495three ways the environment can influence gene expression- medicines, smoking, drinking - stress - diet38
1111358496linkage- is the distance between them is short - less likely to be separated during crossing over - tend to stay together/inherited together39
1111358497what orientation of genes are most likely to be linked?- close together40
1111358498compare the X and Y chromosomes with respect to number of genes- X = 2000+ - Y = few41
1111358499what does the SRY gene do on the y-chromosome?- stimulate production of testosterone42
1111358500why does the father determine the sex of a baby?- contains the Y chromosome (boy) and another X chromosome (girl)43
1111358501x-inactivation- most of one of a female's X chromosome turned off soon after first division of zygote - condenses into a Barr body - mosaic expression of maternal and paternal chromosomes44
1111358502what is the consequence of x-inactivation- incontinentia pigmenti - darker patches of skin color are visible in tissue where the mutated X chromosomes active45
1111358503x-linked genetic disorders nearly exclusively affect males?- males have 1 X chromosome - don't have another allele to make up for faulty copy46
1111358504chromosomes #6look on study guide47
1111358505two examples of x-linked disorders and their basic symptoms- hemophilia A - most common form - mutation in the gene for the clotting protein factor VIII - caused by inbreeding - duchene muscular dystrophy - mutated form of muscle supposed protein - muscles degenerate, lose ability to walk - usually die by age 30 from cardiac or reparatory failure48
1111358506chromosomes #8look on study guide49
1111358507cystic fibrosis- fatal usually before age 30 - thickened mucus: clogs airways - infections - treatment: physiotherapy and antibiotics50
1111358508how is cystic fibrosis inherited?- faulty CFTR gene - inherited from both parents51
1111358509huntington disease- progressive degeneration of nervous system - symptoms appear after age 30 - fatal - mutation on chromosome 452
1111358510how is huntington disease inherited- need one copy of faulty gene to have disorder (autosomal genetic disorder)53
1111358511what is sickle cell anemia?- homozygous recessive - one amino acid substitution in hemoglobin - val instead of glu - pleiotropic effects - relatively common for a recessive genetic disorder - heterozygous - confers resistance to malaria54
1111358512why had the recessive allele persisted in the human population?...55
1111358513chromosomes # 12look on study guide56
1111358514non-disjuction- one or more pairs of chromosomes fail to separate during cell division - increases with a woman's age - if such a gamete is fertilized: trisomy or monosomy57
1111358515one example of a genetic disorder resulting from non-disjunction- down's syndrome - defect of chromosome 21 (trisomy 21) - mental retardation, abnormal skeletal development, motor functions delayed, and weaker muscles58
1114112345mitosis: metaphase- chromosomes align at the equator59
1114112346mitosis: anaphase- sister chromatids separate and move to poles60
1114112347mitosis: telephase- two diploid nuclei form61
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