6093300
Description
Flashcards by Emma Allde, updated more than 1 year ago
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Created by Emma Allde
over 9 years ago
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| Question | Answer |
| What occurs during meiosis I | One round of DNA replication; 46 > 92 chromosomes |
| What occurs during meiosis II | Two rounds of cell division the second phase of meiosis consisting of chromatids separating, along with the two diploid cells splitting in two (4 haploid gametes) |
| What are gametes | haploids cells (23 chromosomes) such as an egg or sperm |
| Gametes unite during sexual reproduction to produce what | a diploid zygote |
| What is monogenic inheritance | The manner in which a particular genetic trait or disorder is passed from one generation to the next |
| Autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, multifactorial, and mitochondrial inheritance are examples of what | monogenic inheritance |
| What are the characteristics of sperm production (@) | Maintained throughout lifetime From puberty onwards |
| What are the characteristics of oogenesis (4) | Largely complete at birth Suspended in meiosis I Resumes once a follicle releases its oocyte into the fallopian tube Then arrests at meiosis II |
| Human non-disjunction rate | up to 3 in 100 (if fertilised most are miscarried) |
| What is the concept of Mendelian inheritance | Basic principles associated with the transmission of genetic material, forming the basis of genetics |
| What are Mendel's laws | the law of segregation and the law of independent assortment |
| What is the law of segregation | Genes segregate at meiosis so each gamete gets 1 of the 2 genes from the parent |
| What is the law of independent assortment | Alleles of different genes assort independently during gamete formation |
| What is an allele | a variant of gene |
| What is a dominant allele | an allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state |
| What is a recessive allele | A hidden allele whenever the dominant allele is present |
| What are the 3 examples of Non-Medelian inheritance | Mitochondrial inheritance Cytoplasmic Extranuclear inheritance |
| What makes mitochondrial inheritance non-Mendelian (2) | • Mitochondria contain their own circular genome which encodes 13 polypeptides plus rRNA and tRNA • Mitochondria are inherited exclusively from the mother (sperm cell mitochondria are excluded from the zygote) |
| Mutations in mtDNA affects organs that: | Use high amounts of energy (ATP) e.g. muscle and nerve |
| What are the 3 general characteristics of mitochondrial cytopathy | Can affect both sexes but can only be passed on by the mother Matrileneal Does not follow any of the autosomal or sex-linked inheritance patterns |
| What are the two types of mitochondrial cytopathy | MELAS and LHON |
| What is MELAS | a mitochondrial cytopathy resulting in myopathy (disease of muscle tissue), encephalopathy (disease in which the functioning of the brain), lactic acidosis, stroke-like symptoms |
| What is Leber's hereditary optic neuropathy (LHON) | a mitochondrial cytopathy resulting in rapid loss of vision in both eyes typically occurs in adulthood but can occur any time after adolescence |
| What is pathogenic presentation of Leber's hereditary optic neuropathy (LHON) dependent on | enough cells w/ a predominant amount of mutant mitochondria in the eye |
| What is Cytoplasmic transfer | Healthy and unhealthy cytoplasm (good + bad mitochondria) then fertilised by IVF |
| What is the drawback to Cytoplasmic transfer | Can still pass on unhealthy mitochondria to child |
| Is Cytoplasmic transfer available | Yes but not in the US, banned by FDA in 2001 |
| What are complex disorders | Most human characters are not Mendelian but are controlled by genes at more than one locus (polygenic) |
| What kinds of polygenic traits exist | Discontinuous or continuous |
| What is the feature of discontinuous polygenetic traits | Either is there or it isn't (e.g. type II diabetes mellitus) |
| What is an example of continuous polygenic trait | height |
| What are multifactorial traits | Polygenic and influenced environment |
| What are the four most common disorders showing multifactorial inheritance that currently are the leading causes of death in the developed world | CVD, diabetes mellitus, obesity, mental illness |
| What is indicated by the term concordance rate | the percentage of twin pairs or other pairs of relatives who exhibit the same disorder; used to assess the contribution made by genetics |
| What is the threshold zone | liability of an individual to develop a given disorder depends on a combination of the number of predisposing genes and exposure to environmental factors (e.g. diet) |
| How is the threshold zone for a given disorder determined | Based on a combination of genetic and environmental contributions |
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