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Flashcards in Final Deck (89):
1

Mendel's law of independent assortment

Two different genes will randomly assort their alleles during the formation of haploid cells

2

Mendel's Law of Segregation

The two copies of a gene segregate (or separate) from each other during transmission from parent to offspring

3

Fundamental theory of heredity

Inheritance involves the passing of discrete units of inheritance, or genes, from parents to offspring

4

Dihybrid cross F2 generation ratio

9:3:3:1

5

Monohybrid cross

Mendel's first experiments involved crossing two variants of the same characteristic

6

Asexual reproduction

Generates offspring that are genetically identical to a single parent

- cell division

7

Sexual reproduction

Two parents contribute genetic information to produce an unique offspring

8

A ___ is an organized representation of the chromosomes within a cell.

Karyotype

9

Diploid -

Have two "sets" of chromosomes

10

Members of a pair of chromosomes are called ___.

Homologs

11

Homologous pair of chromosomes

- nearly identical in size
- have the same bending pattern and centromere location
- have the same genes

12

What does asexual reproduction?

Bacteria
Amoeba
Yeast

13

Sister chromatid

Two copies of a replicated chromosome joined at the centromere to form a pair

14

In actively dividing cells, G1, S, and G2 are collectively known as ___.

Interphase

15

Interphase

G1 - cell prepares to divide
S - cell has twice as many chromatids as there are chromosomes
G2 - cell accumulates the materials that are necessary for nuclear and cell division

16

Mitosis

- prophase (nuclear envelope dissociates into small vesicles, the chromatids condense into more compact structures, centrosomes begin to separate, mitotic spindle apparatus is formed)
- prometaphase (centrosomes move to opposite ends of the cell forming spindle poles, spindle fibers interact with the sister chromatids, kinetochore microtubules grow from the two poles, two kinetechores on a pair of sister chromatids are attached to kinetochore MTs on opposite poles)
- metaphase (pairs of sister chromatids align themselves along a plane called the metaphase plate, each pair of chromatids is attached to both poles by kinetochore microtubules)
- anaphase (the connection holding the sister chromatids together is broken, each chromatid, now an individual chromosome, is linked to only one pole, kinetochore MTs shorten, polar MTs lengthen)
- telophase (cytokinesis, chromosomes reach there respective poles and decondense, the nuclear membrane reforms to form two separate nuclei, quickly followed by cytokinesis)

17

What does sexual reproduction?

Eukaryotic organisms

18

Haploid -

They contain a single set of chromosomes

19

Meiosis I

Prophase I (the chromosomes condense, the nuclear envelope breaks down, crossing-over occurs)
- leptotene (replicated chromosomes condense)
- zygotene (synapsis begins)
- pachytene (a bivalent has formed and crossing over has offered)
- diplotene (synaptonemal complex dissociates)
- diakinesis (nuclear membrane breaking apart, end of prophase I)
Prometaphase I
Metaphase I (pairs of homologous chromosomes move to the equator of the cell)
Anaphase I (homologous chromosomes move to opposite poles of the cell)
Telophase I (chromosomes gather at the poles of the cells, the cytoplasm divides)
Prophase II (a new spindle forms around the chromosomes)
Metaphase II (chromosomes line up at the equator)
Anaphase II (centromeres divide, chromatids move to the opposite poles of the cells)
Telophase II (a nuclear envelope forms around each set of chromosomes, the cytoplasm divides)

20

Penetrance -

Whether gene penetrates enough in order to express or not

21

Expressivity -

The degree to which the trait is expressed

22

X-linked -

This pattern involves the inheritance of genes that are located on the X chromosome

23

Sex-influenced inheritance

This pattern refers to the effect of sex on the phenotype of the individual

24

Sex-limited inheritance

This refers to traits that occur in only one of the two sexes

25

Lethal alleles

An allele that has the potential of causing the death of an organism

26

Incomplete dominance -

Occurs when the heterozygote has a phenotype that is intermediate between either corresponding homozygote

27

Overdominance

This pattern occurs when the heterozygote has a trait that is more beneficial than either homozygote

28

Codominance

Occurs when the heterozygote expresses both alleles simultaneously without forming an intermediate phenotype

29

Mitosis vs meiosis

- mitosis produces two diploid daughter cells
- meiosis produces four haploid daughter cells
- mitosis produces daughter cells that are genetically identical
- meiosis produces daughter cells that are not genetically identical

30

Evaluating the validity of a hypothesis

Scientific method
Chi square test

31

How are alleles dominant?

- gain-of-function - protein encoded by the mutant gene is changed so it gains a new or abnormal function
- dominant-negative - protein encoded by the mutant gene acts antagonistically to the normal protein
- haplosufficiency - loss-of-function, heterozygote does not make enough product to give the wild type phenotype

32

ABO blood type inheritance

- Type O people can only accept type O
- type O can donate to anyone
- mother A type A (IaIa Iai)
Not the father AB IaIb
Child O (need a little i from both parents)
Father could be A, B, O(ii)

33

Epitasis -

When the alleles of one gene mask the phenotypic effects of the alleles of another

34

Extranuclear inheritance

Involves genes in organelles other than the nucleus: mitochondria and chloroplasts

35

Maternal effect

An inheritance pattern for certain nuclear genes in which the genotype of the mother directly determines the phenotype of her offspring

36

How to identify center gene gene in 3-point cross

Map distance

37

Inversion -

A change in the direction of part of the genetic material along a single chromosome

Inversion loop must form

38

Robertsonian translocation

Familial Down syndrome

Most common chromosomal rearrangement in humans

39

Euploidy -

Variation in the number of complete sets of chromosomes

Occur occasionally in animals and frequently in plants

40

Aneuploidy -

Variation in the number of particular chromosomes within a set

Abnormal condition

41

Endopolyploidy -

Diploid animals sometimes produce tissues that are polyploid

42

Autopolyploidy -

Complete nondisjunction can produce an individual with one or more sets of chromosomes

43

Alloploidy -

A much more common mechanism for changes in the number of sets of chromosomes

44

Hardy-Weinberg
Given allele, find frequency of heterozygotes

Frequency of heterozygous carriers is 2pq

45

Phases of cell cycle

G1 (cell growth)
S (DNA synthesis)
G2 (cell growth)

46

Monosomy -

Having a diploid chromosome complement in which one chromosome lacks its homologous partner

47

Twin spots

Consist of two genetically different clones of neighboring cells in a background of normal cells

48

Photolyase

DNA repair enzymes that repair damage caused by exposure to ultraviolet light

49

Telomere

Essential part of human cells that affect how our cells age

Caps at the end of each strand of DNA that protect our chromosomes

50

Rho protein

Binds to the transcription terminator pause site, an exposed region of single stranded RNA after the open reading frame at C-rich/G-poor sequences that lack the obvious secondary structure

Transcription protein in prokaryotes

51

Nucleoside

A compound commonly found in DNA or RNA, consisting of a purine or pyrimidine base linked to a sugar

52

Chromosomes of ___ include how many...

Thousands

53

Diameter of a double helix

2nm

54

Function of DNA polymerase

To make DNA from nucleotides, the building blocks of DNA

55

Function of RNA polymerase

Enzyme that produces primary transcript RNA

56

Sigma factor

Protein needed only for initiation of RNA synthesis

57

Cis-acting elements

- DNA sequences such as the TATA box, enhancers, and silencers exert their effects only over a particular gene

- possibly far from the core promoter, are always found within the same chromosome as the genes they regulate

- "next to"

58

Trans-acting factors

- regulatory genes that bind to such elements
- "across from"

59

Enhancers -

Activating sequences

Needed to stimulate transcription

60

Silencers

DNA sequences that are recognized by transcription factors that inhibit transcription

61

Promoter

Provides a site for beginning transcription

62

Terminator

Specifies the end of transcription

63

Anticodons

3-nucleotide sequences that are complementary to codons in mRNA

64

Allolactose in lac operon system

The ability of the lac repressor to bind to the operator site depends on whether or not allolactose is bound to it.

Allolactose is the inducer

The binding of allolactose alters the function of lac repressor because it prevents it from binding to the DNA

65

Monogenic disorder short answer

-Cystic fibrosis
- Located on human chromosome 7
- encodes a protein called the cystic fibrosis transmembrane conductance regulator (CFTR)
(Regulates ion transport across the cell membrane)
- recessive disorder or humans
- a person must inherit two copies of a defective CF gene - one copy from each parent - to have the disease
- the mutant allele creates an altered CFTR protein that ultimately causes ion imbalance (leads to abnormalities in the pancreas, intestine, sweat glands, and lungs)

66

Oncogene

Mutant gene that promotes cancer

A higher expression of an oncogene may cause a higher rate of cell division

67

Tumor suppressor genes

A gene that functions to inhibit cancerous growth

A decrease in the expression of tumor suppressor genes may allow cancer to occur

68

Lysogenic cycle

Phage does not direct the synthesis of new phages and does not kill the bacterial cell that acts as its host

Can exist in dormant stage for a long time

If cII protein accumulates to sufficient levels

69

Holliday junction

A site where an unresolved crossover has occurred between two homologous chromosomes

70

Mediator

A protein complex that interacts with RNA polymerase II and various regulatory transcription factors

Depending on its interactions with regulatory transcription factors, mediator may stimulate or inhibit RNA polymerase II

71

Operator

A sequences of nucleotides in bacterial DNA that provides a binding site for a genetic regulatory protein

Lac repressor

72

Lac repressor

Protein that regulates the lac operon by binding to the operator site and repressing transcription

73

Shine-dalgarno sequence

A sequence in bacterial mRNAs that functions as a ribosomal binding site

74

Transposon

Type of transposable elements that moves via transposase

Simple transposition

Widely found in bacterial and eukaryotic species

75

Trp repressor

Trp operon is regulated by the trpR gene, which encodes the trp repressor protein

When tryptophan levels within the cell are very low, the trp repressor cannot bind to the operator site

76

Wobble

Rules that govern the binding specificity between the third base in a codon and the first base in an anticodon

77

Pedigrees

Open circle - female
Open square - male
Diamond - sex unknown
Open with line through - deceased
Open with no line - unaffected
Filled in - affected

78

cross

When two distinct individuals with different characteristics are bred to each other

79

Basal transcription apparatus

The minimum number of proteins needed to transcribe a gene

80

DNA replication

- Topoisomerase II (DNA gyrase) travels in front of DNA helicase and alleviates positive supercoiling
- single-strand binding proteins
- RNA primers
- primase synthesizes rna strands by the linkage of ribonucleotide
- DNA polymerase responsible for synthesizing the DNA of the leading and lagging strands

81

Homologous recombination

Requires the participation of many proteins that catalyze different steps in the recombination pathway

Single-strand binding protein

82

Human antibodies

Proteins produced by the immune system of vertebrates

B cells

83

Most sequence variation in humans is due to..

SNPs

84

Chromosome structure

Centromere in middle

85

Chemical bonds in DNA

Sugar deoxyribose, a phosphate group and complementary nitrogenous base pairs

Sugar-phosphate backbone

Base pairs linked by hydrogen bonds

86

Insertion

Mutations in which extra base pairs are inserted into a new place in the DNA

87

Deletion

Section of DNA are lost or deleted

88

Frameshift

Insertions and deletions can alter a gene so that it's message is no longer correctly parsed

89

Substitution

Mutation that exchanges one base for another