Lecture--Chapter 6 Flashcards

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1
Q

What are the characteristics of chloroplast DNA?

A
  1. A single, circular chromosome of double stranded DNA, having 110-120 and about 150k base pairs.
  2. Located in typically 10 or more nucleoids, with about 60 chromosomes per organelle.
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2
Q

Inheritance by random sorting during cytokinesis:

A

chloroplast inheritance

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3
Q

Inheritance where traits are transmitted through the cytoplasm of the egg:

A

maternal inheritance

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4
Q

The mixture of more than one type of organellar genome within a cell or an individual:

A

heteroplasmy

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5
Q

What are the characteristics of mitochondrial DNA?

A
  1. A single, circular chromosome of double stranded DNA, but with a large size variance among different organisms.
  2. Located in typically just a few nucleoids, with < 10 chromosomes per organelle.
  3. Human mitochondrial genome has about 17k base pairs.
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6
Q

transmission of mitochondria by sperm in species that generally have maternal inheritance

A

paternal leakage

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7
Q

Mitochondria are constantly exposed to:

A

reactive oxygen species

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8
Q

What are the 2 ways in which mitochondrial diseases occur?

A
  1. Mitochondrial DNA mutations occur at high rates and their DNA repair mechanisms are extremely limited.
  2. Human mitochondrial disease can be transmitted by a maternal inheritance pattern.
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9
Q

a relationship in which one organism lives inside a host

A

endosymbiosis

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10
Q

“life took over the earth not by combat, but by networking”

A

Lynn Margulis

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11
Q

refers to a gene or chromosome modification that alters gene expression and phenotype, does not involve a change in the DNA sequence, and does not persist for many generations

A

epigenetics

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12
Q

Characteristics of epigenetics:

A
  1. Occurs early during production of gametes or during embryo development
  2. Includes imprinting, gene silencing, position effect, reprogramming, carcinogenesis, maternal effects
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13
Q

the process by which certain genes are expressed in a parent of origin specific manner

A

genomic imprinting

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14
Q

Characteristics of genomic imprinting:

A
  1. Imprinted alleles are silenced

2. Imprinting has been observed in insects, mammals, and flowering plants

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15
Q

the process by which offspring express only one of the two parental alleles

A

monoallelic expression

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16
Q

the mouse lgf2 gene encodes a growth hormone called:

A

insulin-like growth factor 2

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17
Q

Characteristics of lgf2 gene:

A
  1. Mutation of the allele, lgf2- produces a defective protein.
  2. Functional lgf2 gene is necessary for normal size.
  3. The mutation can lead to dwarfism–depending on the source of the allele.
  4. Imprinting results in the expression of the paternal allele, but not the maternal allele.
18
Q

Paternal wt allele + maternal lgf2- —->:

A

normal offspring

19
Q

Paternal lgf2- allele + maternal wt allele —->:

A

dwarf offspring

20
Q

DNA methylation affects:

A

gene expression

21
Q

prevent transcription:

A

silencing

22
Q

imprinting control region:

A

segment of DNA that is methylated or not in paternal vs. maternal chromosome

23
Q

Characteristics of DNA methylation:

A
  1. Usually, but not always, prevents transcription
  2. Addition of one or more methyl groups to an imprinting control region
  3. Can involve a single gene, even part or all of a chromosome
24
Q

Genomic imprinting process: Imprinting occurs during:

A

gametogenesis

25
Q

Genomic imprinting process: The imprint is maintained:

A

during embryogenesis and in adult somatic cells

26
Q

Genomic imprinting process: The imprint is ____ and _____ in germ cells.

A

erased; reestablished

27
Q

With imprinting:

A

either the female or male alleles can be the transcriptionally inactive form

28
Q

focuses on nutritional and environmental factors that influence epigenetic gene regulation

A

environmental epigenetics

29
Q

expresses a signaling protein that determines whether a mammal’s coat is banded or a solid colour:

A

Agouti gene — agouti (banded) or non-agouti (solid colour)

30
Q

Characteristics of the agouti gene:

A
  1. In cats, the agouti dominant results in a tabby pattern

2. In mice, the agouti dominant results in yellow, fat individuals

31
Q

The Agouti Mouse Cross Experiment:

A

(A) control: agouti female x agouti male —> fat yellow babies
(B) experiment:
1. 1/2 of mated females fed normal mouse chow —> fat yellow mice
2. 1/2 of mated females given vitamin supplements —> thin brown mice
3. agouti gene expression was turned off

32
Q

Bisphenol-A Experiment:

A

(A) Mice fed BPA had increased fat, yellow babies, with decreased agouti gene methylation
(B) Dietary supplementation with folic acid gave normal brown mice and restored agouti gene methylation

33
Q

an inheritance pattern for phenotypes determined by the genotype of the mother

A

maternal effect

34
Q

____ observed that the water snail can have a right-handed coiled shell or a left-handed coiled shell

A

Arthur Boycott (1920s); crossing experiment gave a non-Mendelian pattern of inheritance

35
Q

____ crossed the heterozygous F1s, but observed an all dextral phenotype:

A

Alfred Sturtevant

36
Q

The ______ contains lots of gene products produced by maternal cells.

A

oocyte cytoplasm

37
Q

Gene products in the oocyte are based on:

A

the genotype of the mother, not the oocyte

38
Q

Products are transported from ____ to ____ of the oocyte and persist after fertilisation:

A

nurse cells; cytoplasm of the oocyte

39
Q

D gene products cause ___ that promotes a right-handed body plan:

A

egg cleavage

40
Q

Is there a maternal effect in humans?

A

Probably, but there is little firm evidence–many may result in embryos failing to develop; some studies have suggested maternal effect on height and systolic blood pressure.