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Anth 1026 > Ch3 Heredity and Evolution > Flashcards

Ch3 Heredity and Evolution Flashcards

1
Q

Cells

  1. Specialized
  2. Stem
  3. Prokaryotic
  4. Eukaryotic
A
  1. Specialized cells
    - tissue cells (bone, skin, nerve, muscle, blood)
    - sex cells (sperm, ovum)
  2. Stem cells
    - embryonic and adult
  3. Prokaryotes (lack nucleus)
    - Earliest organisms 3.7 billion years ago (bya)
    - Most diverse and successful life form today
  4. Eukaryotes (have nucleus)
    - Arose1.5-1.0 bya
    - Gave rise to multicellular organisms
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2
Q

Meiosos

A

Production of sex cells (gametes) via two cell divisions = four daughter cells

  • Haploid: single set of unpaired chromosomes
  • 23 single-stranded chromosomes
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3
Q

Mitosis

A

Division of somatic cells resulting in production of two daughter cells

  • 23 double-stranded
  • 46 single-stranded chromosomes
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4
Q

The Building Blocks of Life (6)

A
  1. Nucleotides
  2. Double Helix
  3. Gene
  4. Chromosome
  5. Nucleus Functional Human
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5
Q

Gene

A
  • A sequence of DNA (or RNA) that codes for a molecule that has a function
  • Will always have 2 copies
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6
Q

Chromosome

A
  • A chromosome consists of a long strand of DNA containing many genes
  • A human chromosome can have up to 500 million base pairs of DNA with thousands of genes
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7
Q

To Make a Protein

A 
RNA 
- single-stranded, uracil instead of thymine, different sugar 
mRNA
- transcription 
tRNA
- translation
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8
Q

Gregor Mendel

A

1866 paper “Experiments in Plant Hybridization”

  • Inheritance in pea plants
  • Considered father of genetics

Genetics + Natural Selection = The Modern Synthesis

  • Discrete or Mendelian traits: present or absent
  • Phenotype or genotype
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9
Q

Alleles

A
  • Alternate forms of a gene that occur at the same locus on homologous chromosomes
  • Dominant versus Recessive
  • Homozygous vs. Heterozygous
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10
Q

Allele Misconceptions

A
  • Dominant alleles are not “stronger”, “better” or more common
  • Often they are quite rare (Huntington disease)
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11
Q

Environmental factors on traits

A
  • Genotypes set limits, but also interact with the environment
  • Phenotypic expressions are affected by this interaction
  • Ex. Height is determined by genes, but childhood nutrition and development can affect height
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12
Q

Punnett Square

A
  • Can use to determine if alleles are:
    homozygous ‘TT’ or ‘tt’
    heterozygous ‘Tt’
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13
Q

Monogenic Traits

A
  • Controlled by a single gene

- Co-dominance, e.g. ABO blood system

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14
Q

Principles of Inheritance:

Segregation

A
  • each sex cell contains only one allele from each parent

- Genes occur in pairs because chromosomes appear in pairs

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15
Q

Independent Assortment

A
  • Distribution of one pair of alleles into the sex cells does not influence the
  • Ex. The colour of your hair does not affect the colour of your eyes
  • Genes controlling different traits are inherited separately from one another
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16
Q

Examples of Sex- Linked genes

A

Sex linked genes on the X chromosome
- Red-green colour blindness
- Hemophilia
More than 20, 000 inheritable traits

17
Q

Modern Synthesis

A

Synthesis of Mendelian genetics and natural selection within evolutionary theory

18
Q

Evolution as a 2-stage Process

A
  1. Production and redistribution of variation
  2. Natural selection acting on this variation
    - inherited differences among individuals differentially affecting their ability to successfully reproduce
19
Q

Variation: Mutations

A
  • Alteration to a gene or chromosome
  • Can be caused by exposure to chemicals, radiation, and sunlight
  • Can be neutral, beneficial or harmful
  • Only passed on if occur in the sex cells
20
Q

Variation: Gene Flow

A
  • Exchange of genes between populations
  • Occurs only when migrants interbreed
  • Ex. African-Americans are largely of West African decent, but due to gene flow, they are estimated to have 20-25 percent of their gene pool come from non-African decent
21
Q

Variation: Genetic Drift

A

‘Random’ factor in evolution and occurs in small populations

  • Common example is founder effect: allele frequency alteration in small populations that are remnants of larger populations
  • May cause a genetic bottleneck - loss of genetic diversity
22
Q

Recombination

A
  • Occurs during meiosis
  • Important source of variation
  • When genetic material is exchanged between homologous chromosomes
  • Happens in the beginning, they switch genes and alleles before meiosis begins
23
Q

Nondisjunction

A
  • Failure of a chromosome to separate properly during meiosis
  • Results in more or less than normal number of chromosomes
  • Trisomy (e.g. Down syndrome)
  • Monosomy (e.g. Turner syndrome)
24
Q

Sickle Cell Anemia

Via alleles

A
  • Most humans are homozygous HbA/HbA and they produce normal hemoglobin
  • Worldwide the HbS allele is very rare
  • People who are heterozygous HbA/HbS have a condition called sickle-cell trait
  • People who are homozygous HbS/HbS have a condition called sickle-cell anemia
25
Q

Sickle Cell Anemia

Symptoms/ stats

A
  • Cause red blood cells reduced ability to transport oxygen through the blood stream
  • Cause difficulties while exercising because of lack of oxygen
  • Can clump together and block capillaries
  • 100,000 deaths per year world wide
  • 40-50,000 individuals (mostly African descent) in USA suffer from this condition
26
Q

Malaria

symptoms and stats

A
  • Kills 1-3 million people every year
  • The parasite invades red blood cells, where they get the oxygen they need for reproduction
  • Fever, headache, chills, nausea, vomiting and frequently death
  • In parts of western and central Africa, 50-75% of 2-9 year olds are affected
  • People with sickle cell anemia have a higher resistance to malaria

Anth 1026 (9 decks)

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