Term
| What is the definition of human genetics? |
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Definition
| the study of heredity in man |
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Term
| What is the definition of medical genetics? |
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Definition
| the study of human genetic variation of medical significance |
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Term
| What is the functional unit of inheritance; a region that codes for a product-either RNA or protein? |
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Definition
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Term
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Definition
| the functional unit of inheritance; a region that codes for a product-either RNA or protein |
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Term
| What is the structure composed of DNA and protein? |
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Definition
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Term
| What is the position of a gene on a chromosome called? |
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Definition
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Term
| What is the definition of an allele? |
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Definition
| an alternate form of a gene occupying the same locus; 2 alleles=diploid complement |
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Term
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Definition
| a permanent, heritable change in the sequence of genomic DNA |
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Term
| Mutations can happen on two different scales; what are they? |
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Definition
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Term
| What is the important benefit of mutations? |
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Definition
*Can give rise to new alleles
*An important mechanism of population variation |
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Term
| What are some examples of neutral, positive, and negative mutations? |
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Definition
Neutral: blue eyes
Positive: Sickle cell trait
Negative: Sickle cell disease, cancer |
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Term
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Definition
a set of characteristics which occur together and are assumed to have a common basis.
Not all characters are present in all individuals
Leads to a range of disease variability within a population |
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Term
| What is a treatment? A cure? |
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Definition
| A treatment fixes symptoms only (makes a patient feel better), while a cure completely fixes the underlying condition |
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Term
| What are the stages in the cell cycle? What occurs in each stage? |
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Definition
G1 (Gap1) phase: major cell growth phase, more organelles
S Phase: DNA replication phase
G2 Phase: making more protein/organelles to prepare for mitosis
M phase: cell division |
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Term
| What is the primary difference between mitosis and meiosis? |
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Definition
| mitosis results in 2 identical copies while meiosis results in haploid cells. |
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Term
| What are the stages in mitosis? What happens at each stage? |
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Definition
Prophase:condensation of chromosomes, nuclear envelope starts to dissolve
Metaphase: centrosomes bind to chromosomes, they line up
Anaphase: sister chromatids separate to either side
Telophase: nuclear envelopes reform, cytokinesis |
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Term
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Definition
-1st stage homologous chromosomes are separated, leaving haploid cells. Recombination occurs at prophase 1
-2nd stage separates duplicate DNA copies of haploid cells |
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Term
| Why is recombination significant? |
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Definition
| Adds quite a bit of genetic diversity, also can cause some abnormalities. |
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Term
| What happens when there is meiotic nondisjunction in meiosis 1? |
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Definition
| 2 homologous chromosomes fail to separate. Final result = 2 cells with 2 copies of the chromosomes (heterodisomy), 2 cells with no copies (nullosomy) |
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Term
| What is nullosomy of a chromosome? |
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Definition
| Complete lack of a chromosome |
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Term
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Definition
| Receiving 2 copies of the exact same chromosome (eg sister chromatids) |
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Term
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Definition
| Receiving a copy of both homologous chromosomes in a single gamete. |
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Term
| What happens when there is nondisjunction in meiosis II? |
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Definition
| sister chromatids fail to separate, one cell ends up with 2 copies of the same chromosome, (isodisomy), one ends up with none (nullosomy) |
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Term
| Describe spermatogenesis. |
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Definition
| Primary spermatocyte undergoes meiosis I to form 2 secondary spermatocytes (haploid). Secondary spermatocytes undergo meiosis 2 to form spermatids which then become sperm |
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Term
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Definition
| All primary oocytes are frozen at prophase 1 of meiosis at ~20 weeks in the womb. When menstruation occurs, the oocyte completes meiosis 1 and releases a first polar body. It immediately begins meiosis 2 but then halts in metaphase 2 until fertilization occurs. |
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Term
| What are some differences between spermatogenesis and oogenesis? |
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Definition
| Spermatogenesis happens throughout reproductive life, while all oocytes are present at birth. Males get 4 gametes per primary gametocyte, females get 1 |
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Term
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Definition
| the study of heredity at the cellular level |
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Term
| What is the clinical role of cytogenetics? |
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Definition
| *Identify chromosomal abnormalities that may be associated with disease and distinguish those from normal variations |
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Term
| What are some of the effects of chromosomal abnormalities? |
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Definition
1) change in phenotype
2) fetal loss
3) genetic disease
4) malignancy |
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Term
| What are some of the statistics on fetal loss? |
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Definition
1 in 13 conceived children have chromosomal abnormality (6/1000 are liveborn)
15% of recognized pregnancy end in abortion, 80% in first trimester
Of spontaneous losses, 60% are chromosomal; of chromosomal losses, 52% are autosomal trisomies |
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Term
| What is the prenatal clinical role of cytogenetics? |
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Definition
| Can conduct amniocentesis, can affect abortion or stillbirth |
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Term
| What is the correlation between chromosomal abnormalities of the fetus and age of the mother? |
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Definition
| Chromosomal abnormalities increase with the age of the mother |
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Term
| What is the postnatal role of cytogenetics? |
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Definition
| can detect features of a known chromosomal disorder; can determine sex in case of ambiguous genitalia |
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Term
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Definition
| 3N DNA genome, usually arises when an extra sperm enters the egg. |
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Term
| What are 3 types of structural, cytogenetic chromosomal abnormalities? |
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Definition
| translocations, deletions, and ring formations |
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Term
| How do we identify chromosomal abnormalities? |
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Definition
| karyotyping (examining size, banding pattern, and centromere position) |
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Term
| What is the difference between metacentric, submetacentric, and acrocentric chromosomes? |
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Definition
metacentric: centromere in middle of chromosome
submetacentric: arms of unequal length
acrocentric: short arm is hard to observe
*p=short arm, q=long arm |
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Term
| Where is the nucleolus organizer region located (NOR)? |
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Definition
| It is located on the stalk of acrocentric chromosomes. It is the location where the nucleolus is formed; contains rRNA genes. |
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Term
| What is the SRY region on the Y chromosome? |
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Definition
| Sex determining region of the Y chromosome |
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