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Genetics Flashcards

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1
Q

Cell Theory

A
  1. all living things are made from cells
  2. cells come from other cells
  3. cells are the basic unit of life
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2
Q

What makes up DNA?

A
  • A sequence of nucleotides are stored in DNA molecules;
  • A 5 carbon sugar called deoxyribose
  • A phosphate group (PO4)
  • One of the four nitrogenous bases (Adenine/Thymine, Guanine/Cytosine)
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3
Q

What is DNA (structure)?

A
  • Double stranded a
  • Alpha helix
  • Nitrogenous bases are held together by hydrogen bond
  • Sugar-phosphate backbone
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4
Q

Why is the sequence of nucleotides relevant?

A

The sequence of nucleotides in DNA determines the order of amino acid in proteins, which is responsible for all characteristics of an organism

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5
Q

What are the organelles necessary for the synthesis of proteins?

A
  • Nucleus: stores the genetic material in eukaryotic cells
  • Ribosomes: made in nucleolus and join the amino acids in a chain
  • Rough endoplasmic reticulum: folds the protein into proper shape and transports them throughout cell
  • Golgi body: adds carbohydrate chains/metal ions or joins subunits if necessary + packages the finished proteins for transport in vesicles
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6
Q

Asexual Reproduction

A
  • Method of reproduction in which 1 individual transmits the hereditary information to the next generation
  • Nucleus divides by mitosis
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7
Q

Mitosis

A

division of nucleus (DNA)

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8
Q

Prophase

A
  • DNA (chromatin) condenses into chromosomes
  • Nuclear membrane breaks down and nucleolus disappears
  • Spindle fibers form from the centrosome as they seperate to opposite poles
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9
Q

Metaphase

A
  • Condensed chromosomes line up on equator guided by spindle fibers which are joined to centromere of sister chromatids
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10
Q

Anaphase

A
  • Centromere splits, forming daughter chromosomes

- Chromosomes are pulled to opposite poles by spindle fibers

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11
Q

Telophase

A
  • Begins once chromosomes have reached opposite poles of the cell
  • Nuclear membrane reforms with nucleolus
  • Daughter chromosomes uncoil
  • Spindle fibers break down
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12
Q

Cytokinesis (why + animal/plant)

A
  • Occurs to divide the cytoplasm and its organelles in it resulting in 2 identical daughter cells
  • Animal: microfilaments pinch cytoplasm in half forming a cleavage furrow
  • Plants: cell plate forms between 2 daughter nuclei, then cell walls form
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13
Q

Sexual Reproduction

A
  • Method of reproduction in which 2 individuals are needed to transmit the hereditary information to next generation
  • Cucleus divides by meiosis
  • Each parent contributes a gametes to offspring in the process of fertilization
    this doubles the amount of DNA (2n) in newly formed cell, called zygote which splits to form embryo
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14
Q

Homologus chromosomes

A

Chromosomes that contain the same genes/genetic information (but not identical); 1 comes from mother and 1 comes from father

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15
Q

Diploid

A

Cells that contain 2 sets of genetic information (2n) or body cells

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16
Q

Haploid

A

Cells that have 1 set of genetic information (n) or sex cells

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17
Q

Gene

A

Portion of DNA with information for 1 protein (aka, eye colour)

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18
Q

Allele

A

Different versions of a gene (blue eyes or brown eyes?

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19
Q

Independant assortment

A

Maternal and paternal chromosomes randomly line up in the middle of the cell during metaphase; orientation of maternal and paternal chromosomes is independant of other pairs

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20
Q

Zygote

A

Egg and sperm fused together after fertilization, divides into an embryo

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21
Q

Tetrad

A

2 homologous chromosomes, each with their sister chromatids

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22
Q

Chiasmata

A

Point that is holding homologous chromosomes together, crossing over occurs here

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23
Q

Synapsis

A

Pairing up of homologous chromosomes to form tetrad

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24
Q

Types of chromosomes in cells

A
  • Sex chromosomes determine sex of individual (1 pair)

- Autosomal chromosomes determine the physical characteristics (1-22 chromosome pairs)

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25
Meiosis goals
1. Reduction division - forms daughter cells with half the number of chromosomes of the parent cell 2. Genetic variability - daughter cells have different combinations of alleles from one another and the parent cell (Crossing over, independant assortment, fertilization)
26
Meiosis I
- Separation of homologous chromosomes | - Produces 2 different haploid cells
27
Interphase I
- 2n | - Each chromosome has 2 sister chromatids
28
Prophase I
- DNA is condensed - Homologous chromosomes pair up, process called synapsis - Points of contact are called chiasmata and the pair of homologous chromosomes is called a tetrad - Crossing over occurs where DNA from non-sister chromatids is exchanged - 2n
29
Metaphase I
- Homologous chromosomes randonly line up on equator with spindle fibres attached to centromere - This is called independant assortment - 2n
30
Anaphase I
- Homologous chromosomes separate - Each chromosome still has 2 sister chromatids - n
31
Telophase I / Cytokinesis I
- Cytoplasm divides and nuclear envelope may reappear and chromosomes may uncoil - Results in 2 different haploid cells - n
32
Meiosis II
- Separation of sister chromatids | - Same thing as mitosis except cells are haploid
33
Prophase II
- Chromosomes condense | - Nuclear membrane disappears
34
Metaphase II
Chromosomes line up on the equator
35
Anaphase II
Sister chromatids separate into daughter chromosomes
36
Telophase II/Cytokinesis II
- Chromosomes uncoil - Cytoplasm gets divided - Creates 4 different haploid cells
37
Asexual reproduction: advantages
- Fast - Only 1 parent - If is well adapted to environment, so are offspring (good in constant environment)
38
Asexual reproduction: disadvantages
- If environment changes (global warming, ice age), can’t adapt
39
Sexual reproduction: advantages
- Genetic variability means some individuals survive if environment changes
40
Sexual reproduction: disadvantages
- Slow | - Requires 2 parents
41
Mitosis vs meiosis: differences
- Cellular processes involved (asexual reproduction, growth, repair vs sexual) - Type of cell in which it occurs (sex vs somatic) - # of divisions - # of daughter cells - Chromosomes in daughter is different - Genetic info (different vs identical) - Crossing over and synapsis doesn't occur in mitosis
42
Mitosis vs meiosis: similarities
- Both duplicate DNA | - Chromosomes in parent is 2n
43
Non-disjuction
Failure of homologous chromosomes to separate during Anaphase I or of sister chromatids to separate during Anaphase II
44
Aneuploidy
A condition with extra or missing chromosomes
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monosomy
If a sex cell of one parent is missing a chromosome, then the offspring will have 1 copy of that chromosome
46
trisomy
If a sex cell of one parent has an extra chromosome, then the offspring will have 3 copies of that chromosome
47
polyploidy
In general, too many chromosomes
48
1. Genes added onto other chromosome
- Deletion of genes for one chromosome | - Duplication of genes for the other chromosome
49
2. Part of a chromosome goes to a non homologous chromosome
- Translocation | - XYZ not homologous with EF!
50
3. Genes got switched around
- Inversion of genes | - Genes don’t work unless they are in the proper order; ABCDEF not ABCDFE
51
Fertilization
Process of gametes fusing together to form zygote
52
Process of fertilization?
Female/male + meiosis = female/male gamete + female/male gamete = fertilization = zygote
53
Cri-du-chat
- partial delection in chromo #5 | = larynx abnormal. so sounds like a cat; mentally challenged
54
Fragile-X syndrome
- part of x chromosome breaks out | = abnormal facial features, mentally challenged
55
Down syndrome
- trisomy 21 (3 copies of chromo 21) | = abnormal facial features, mentally challenged
56
Klinefelter syndrome
- XXY (extra chromosome) | = sterile male with breasts, normal intelligence
57
Turner syndrome
- XO (missing chromosome) | = sterile female, partially developed secondary sexual characteristics, normal intelligence
58
Karyotype
A picture showing all of the homologous chromosomes so they can clearly see chromosomal abnormalities
59
Semi-conservative
DNA replication; strands separate, free nucleotides join their complementary base. (half of each daughter DNA molecule comes from the parent molecule and the other half is newly made.)
60
The 2 strands of a DNA molecule are...
Complementary to each other
61
What does the cell theory tell us about traits?
That traits must be passed form parent to daughter cell in the form of deoxyribonucleic acid if cells come from pre-existing cells
62
Interphase
- The cell grows (G1) and caries out the reactions necessary for living - Replicates DNA (Synapsis) for mitosis or meiosis - Synthesis of molecules occur (G2)
63
Genome def
Complete DNA sequence of an organism
64
Are sex chromosomes homologous?
No! They are not similar, but they are always paired together.
65
Meiosis def
- Cellular process that forms cells with 1/2 the amount of chromosomes in a diploid cell so that when gametes combine in fertilization, a zygote is formed
66
Crossing-over
Exchange of DNA of homologous chromosomes at chiasmatas
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