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Biology 11 > Unit 2 - Genetics > Flashcards

Unit 2 - Genetics Flashcards

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1
Q

Genetics

A

is the field of biology that involves the study of how genetic information is passed from one generation of organisms or cells to the next

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2
Q

The Cell Theory States..

A
  1. all living things are composed of one or more cells
  2. cells are the smallest units of living organisms
  3. new cells come only from pre-existing cells by cell division
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3
Q

The cell cycle

Somatic Cell

  • all somatic cells go through cell cycles
  • as one cell completes a cycle, it becomes two cells
A

is a plant or animal cell found in the body of an organism

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4
Q

the cell cycle

What does the duration of the cell cycle depend on?

A
  • the cell type
  • the organism
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5
Q

For healthy/actively dividing animal cells, how long does the cell cycle last?

A

12 to 24 hours

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6
Q

In multi-cellular organisms, cell division (cell cycling) has what three functions:

A
  1. growth of the organism
  2. repair of tissues and organs
  3. maintenace to replace dead cells (ex. skin cells)
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7
Q

What are the three stages of the cell cycle?

A

three main stages:
1. Interphase: growth and intense cell activity
——G1, S, G2
2. Mitosis: cell’s nucleus and genetic material divide
——First part of cell division
3. Cytokinesis: division of the cell cytoplasm and creation of new cells
——-Second part of cell division

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8
Q

How long is a cell in interphase and cell division?

A

90% in Interphase
10% in Cell Division

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9
Q

First stage

Parts of Interphase

A

G1 phase: rapid growth and cell activity
S phase: DNA synthesis and chomatin replicates
G2 phase: further growth and cell prepares for division

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10
Q

second stage

Mitosis

definition and parts

A

before the cell divides the cell must undergo mitosis, which is the separation of cells replicated genertic material

PMAT - Prophase, Metaphase, Anaphase, Telophase

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11
Q

chromosome

A

a structure in the nucleus that contains DNA

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12
Q

sister chromatid

A

one of two chromosomes that are genetically identical and held together at the centromere

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13
Q

centromere

A

the region where two sister chromatids are held together in a chromosome

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14
Q

spindle fiber

A

a microtubule that controls the movement of chromosomes within a cell

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15
Q

centrosome

A

a structure that forms spindle fibers

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16
Q

Prophase

A
  • Cell’s chromatin condenses into chromosomes (which contain DNA)
  • Nuclear membrane breaks down,** nucleolus disappears**
  • Spindle fibres are formed from the centrosomes as they move from opposite poles (sides) of the cell
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17
Q

Metaphase

A
  • Spindle fibres control the chromosomes to the equator line of the cell
  • The spindle fibres from opposite poles of the cell, attaches to the centromere of each chromosome
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18
Q

Anaphase

A
  • Each centromere splits apart, sister chromatids separate from each other
  • The separated sister chromatids are now called chromosomes
  • Spindle fibres shorten and pull the chromosomes to opposite poles of the cell
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19
Q

Telophase

A
  • Begins when chromosomes reach opposite poles of cell
  • Chromosomes unwind into strands of chromatin
  • Spindle fibres break down, nuclear membrane forms around the new set of chromosomes at each pole
  • Nucleolus forms within each new nucleus
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20
Q

Cytokinesis

A

is the division of the cytoplasm (pinches) or cell wall (splits) to complete the creation of two new daughter cells

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21
Q

The structures of genetic material

what is DNA comprised of?

A

nucleotides, each of which is made up of:
* a sugar (deoxyribose)
* a phosphate group
* a base.
There are four bases: adenine (A), guanine (G), cytosine (C), and thymine (T).

Across the middle of the helix:
A pairs with T, and C pairs with G.

—-DNA is shaped like a long, spiraling double helix.

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22
Q

What are chromosomes made up of?

A

compounds called deoxyribonucleic acid (DNA)

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23
Q

DNA is the master copy of information used to consruct an organism? true or false

A

true

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24
Q

P.A Levine showed that DNA was made of a seri es of units called nucleotides? true or false

A

true

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25
Q

What nucleotides have a double ring structure and belong to a group called purines

A
  • adenine
  • guanine
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26
Q

what nucleotides have a single ring structure and belong to a group called pyrimidines

A
  • thymine
  • cytosine
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27
Q

Complementary Base Pairs

A

Nitrogen bases:
* Adenine pairs Thymine
* Guanine pairs Cytosine

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28
Q

The order of base pairs in a DNA molecule make up the ____ of an organism

A

genetic code

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29
Q

DNA

genetic code

A

is a type of code that DNA stores information

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30
Q

Proteins are made up of ____ kinds of amino acids ____ together in a certain order in each ____

A

20, linked, protein

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31
Q

Linked amino acids form long chains called ___

A

polypeptides

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32
Q

two or more polypeptides are joined to make a ____

A

protein

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33
Q

The genetic code

It takes three nucleotide combinations in order to have enough different ____ to code for all 20 ________

A

code words, amino acids

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34
Q

the genetic code

Each set of three bases is known as a ____

A

codon

  • some may code for the same amino acid
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35
Q

RNA also has 4 bases- rather than thymine, RNA contains ____ which forms the base pair with Adenine

A

Uracil (U)

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36
Q

Stop Codons?

A

this means that production is complete, and no more amino acids should be added

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37
Q

Diploid #

A
  • meaning double
  • (2n)= 46 Chromosomes
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38
Q

Haploid #

A
  • meaning half 46
  • (n)= 23 Chromosomes
39
Q

Sexual Reproduction

A
  • requires two parents and produces fertile offspring
  • this involves the fusion of male and female reproductive cells (gamates)
  • which fertilize to form a fetus (zygotes)
40
Q

Meiosis

definition

A

the process that produces gamates with a haploid number (23) of chromosomes

41
Q

what are the two outcomes of meiosis

A
  1. genetic reduction: a form of cell division that produces daughter cells with half the number of chromosomes of the parent cell
  2. genetic recombination: the products of meiosis have different combinations of alleles
42
Q

Meiosis involves ____ complete cycles of PMAT, called Meiosis I and Meiosis II

A

2

43
Q

Meiosis I

cell is diploid

A
  • Interphase: the replication of the DNA
  • Prophase I: the homologous chromosomes line up side-by-side in an alignment called synapsis. The homologous chromosomes are held tightly along their lengths
    while some segments are exchanged. This increases genetic diversity.
  • Metaphase I: homologous chromosomes are lined up together along the equator.
  • Anaphase I: homologous chromosomes are separated
  • Telophase I: the homologous chromosomes uncoil and spindle
    fibres disappear

—followed by cytokinesis, in which a nuclear membrane forms around each group of chromosomes, creating haploid cells

44
Q

Sex chromosomes differ in size and shape. Is the X chromosome larger than the Y chromosome?

A

yes

44
Q

Meiosis II

cell is haploid

A
  • prophase II and metaphase II: similar to mitosis
  • anaphase II: sister chromatids are separated
  • telophase II and cytokinesis create four haploid cells
44
Q

how many chromosomes do humans have?

A
  • 1 pair of sex chromosomes (x or y)
  • 22 pairs of autosomes
  • total of 46 chromosomes
45
Q

Human females possess ____ X chromosomes

A

2 (XX)

46
Q

Human males possess ____ X chromosome and ____ Y chromosome

A

1, 1 (XY)

47
Q

Karyotype

A

is a display of a persons set of chromosomes. The chromosomes are collected and stained.
* The chromosome pairs are arranged and numbered in order of their length,
from longest to shortest.
* The sex chromosomes are placed last in a karyotype.
* Note that the banding
patterns between homologous chromosomes are different in this image because of the type of dye that was used to stain

48
Q

Spermatogenesis

A

is the process that produces sperm in male animals

49
Q

Oogenesis

A

produces eggs in females

50
Q

Births

Fraternal vs Identical twins

A

Fraternal:
* not identical
* more than one egg released

Identical Twins
* identical
* single zygote splits in first few days

51
Q

Females tend to be a carrier of a diseased allele? true or false

A

true

52
Q

X-linked disorders

affect more males than females

A
  • hemophilia
  • colour blindness
  • duchenne muscular dytrophy
  • baldness
53
Q

genetic variation

independent assortment and crossing over

A

During meiosis, genetic variation is ensured in two ways:
1. In a process called independent assortment, gametes are created that carry different combinations of maternal and paternal chromosomes. This occurs during metaphase I, when each homologous chromosome is randomly oriented towards one of the poles. This alone can produce over 8 million different chromosome combinations.
2. In a process called crossing over, genetic material between maternal and paternal chromosomes is exchanged. This occurs during prophase I in which non-sister chromatids exchange genetic material in multiple sections.

54
Q

What errors can occur during cross over of chromosomes?

A

When chemical bonds are re-formed during crossing over, errors can occur that can result in the following:
* deletion of a chromosome section
* duplication of a chromosome section
* inversion of a chromsome section
* translocation of a chromosome section to a different chromosome

55
Q

error in chromosome number

non-disjunction

A
  • this is where homologous chromosomes or sister chromatids do not separate during meiosis (anaphase I or anaphase II).
  • this produces gametes that have too many or too little chromosomes.
  • example: Trisomy 21, are three copies of chromosome 21, which results in Down Syndrome.
  • Monosomy is the term used for a single chromosome copy error.
56
Q

In 1853, Gregor Mendel studied ____. Where he conducted a series of experiments on plants over an ____ year period.

A

heredity, 8

57
Q

Mendel said there are three key points to any successful experiment in biology, those were?

A
  1. Choosing the appropriate organism to study
  2. Designing and performing the experiment correctly
  3. Analyzing the data accurately and properly
58
Q

Mendel studied what plant?

A

the pea plant

59
Q

Why did mendel chose a pea plant to study and experiment with?

A

four main reasons:
1. Pea plant was commercially available
2. Easy to grow and mature quickly
3. Sexual organs are enclosed in the flower (ability to self pollinate or fertilize eggs with pollen)
4. Different varieties of the pea plant had different traits

60
Q

Mendel examined 7 different traits, each trait had only ____ variations

A

2

61
Q

gregor mendel

purebreds

A
  • descended from ancestors of
    a distinct type, or breed
  • used selective breeding methods to continue breeding purebreds

Example: he bred only TALL plants together to obtain tall plants, and he bred SHORT plants together to obtain only short plants

62
Q

gregor mendel

True breeding

A

he was able to produce plants
that grew either short OR tall

63
Q

in pea plants, what traits were dominant and/or recessive?

A

Dominant:
* round
* yellow
* purple flowers
* axial position
* green pod
* inflated pod
* tall plant height

Recessive:
* wrinkled
* green
* white flowers
* terminal position
* yellow pod
* constricted pod
* short plant height

64
Q

mendels first experiment: monohybrid cross

once mendel had his ____ bred plants, he called them the ____ generation (P generation)

A

purebred, parent generation

65
Q

mendels first experiment: monohybrid cross

then, he crossed a true-breeding tall pea plant with a true-breeding short pea plant. the offspring from this cross were called the ____ generation (F1 generation). mendel called this generation hybrid plants bceause they were a cross between two ____ plants. calling this a monohybrid cross

A

filial, purebred

66
Q

mendels first experiment

After Mendel crossed a purebred tall plant with a
purebred short plant, he expected the F1 generation (hybrids) to be of medium height. In fact they were all 100% ____.

A

tall

67
Q

dominant trait

A

characteristic that is always expressed, or always appears, in an individual

68
Q

recessive trait

A

a characteristic that is latent (present but inactive) and is therefore not usually expressed within an individual

  • A recessive trait may be expressed if only recessive traits exist within the individual
69
Q

Principle of Dominace

A

when individuals with contrasting traits are crossed, the offspring will express only the dominant trait

70
Q

Law of Segregation

experiment based

A
  • Next, Mendel conducted an experiment by breeding the F1 generation
  • He allowed the hybrid tall plants of the F1 generation to self pollinate
  • This produced the second filial generation, or F2 generation
  • 3 of the 4 plants in the F2 generation were tall, while 1 was short
  • He repeated the experiment, with seven traits
  • He obtained the same results time after time
  • The F2 generation resembled one parent from the P generation 75% of the time, and the other parent from the P generation 25% of the time

This has a Ratio 3:1

71
Q

Mendelian ratio

A

3:1

72
Q

Law of Segregation States

definition based

A

inherited traits are determined by pairs of “factors”
* These factors segregate (separate) in the gamete, with one in each gamete
* Factors were “genes”- the part of the chromosome that governs the expression of a particular trait

  • A gene can occur in alternate forms called alleles
  • When two alleles are present, a dominant allele may prevent the expression of a recessive allele
73
Q

Alleles are represnted with?

A

letters, either uppercase for dominant or lowercase for recessive

74
Q

Punnet Squares

A
  • are used to calculate the probability of inheriting a particular trait. It is a simple method of illustrating all possible combinations of gametes from a given set of parents
  • Possible gametes are listed on the top for one parent, and across the side for the second parent
75
Q

genotype

A

genetic make up of an organism
* ex. (Tt -50%, TT-50%)

76
Q

Phenotype

A

apperance of the trait of an organism
* ex. (2/4 black, 2/4 pink)

77
Q

Mendelian ratio for genotype

A

1:2:1
* 1 homozygous dominant
* 2 heterozygous
* 1

78
Q

```

~~~

Pedigrees

A
  • Records extending across several generations
    can be arranged in the form of a family
    pedigree
  • Pedigrees display simple dominant traits
    (traits that have only two possible alleles-
    dominant or recessive)
  • Remember!!!! Both alleles must be recessive
    for an individual to express the recessive trait
  • Traits that can be expressed in this way
    include: hair line, freckles, length of eyelashes,
    tongue rolling
79
Q

The Inheritance of Two Traits

Dyhybrid Cross

Mendels second experiment: a dyhybrid cross

A

a cross of two organisms that differed in two traits.
* example: pea shape and pea colour.

80
Q

The Inheritance of Two Traits

Law of Independent assortment

A
  • proposed by Mendel that states that
    the inheritance of alleles for one trait does not affect the inheritance of
    alleles for another trait
  • different pairs of alleles are passed to the
    offspring independently of each other.
  • this results in a 9:3:3:1 ratio.
81
Q

beyond mendels laws

What did mendel suggest?

A

some organisms do not express the
dominant allele, and exhibit different patterns
of inheritance

82
Q

Incomplete Dominance

A
  • Not all traits are purely dominant or purely
    recessive
  • When this happens, a blending of the two
    traits can occur
  • Apparent blending of traits to give an
    intermediate expression can occur in
    individuals that are heterozygous

Example: White or Red flowers are homozygous,
while Pink flowers are heterozygous

RR- red flower

R’R’- white flower and produce no pigment

RR’ OR R’R- pink flower (incomplete
dominance)

83
Q

Co-Dominace

A
  • both alleles for a trait can be
    dominance
  • BOTH alleles are expressed in the heterozygous
    individual

Example: Chickens- governed by two dominant alleles for feather
colour

BB Black feathers

WW White feathers

BW Black and White feathers

84
Q

Multiple Alleles

A

Many genes have more than two alleles, or multiple alleles

85
Q

Multiple Alleles example: blood

A

Blood Type- A, B, O:

  • A type blood- A glycoproteins
  • B type blood- B glycoproteins
  • AB type blood- A and B glycoproteins
  • O type blood- neither glycoprotein
86
Q

Human Blood Types

A
  • Types A and B are homozygous, and may be
    heterozygous (mixed with blood type O)
  • Type AB- homozygous (individual would have to
    inherit A and B dominant alleles)
  • Type O- homozygous recessive
87
Q

The blood type considered the “universal donor”?

A

type O

88
Q

The blood type considered the “universal recipient”

A

type AB

89
Q

Can A-type donors, donate blood to type AB-recipients?

A

Yes, A-type donors can donate blood to type AB-recipients.

90
Q

Create a chart in your notebook, showing donor/recipient types

A
  • O——-All blood types (O-, O+, A-, A+, B-, B+, AB-, AB+)
  • O+——–O+, A+, B+, AB+
  • A- ——–A-, A+, AB-, AB+
  • A+——–A+, AB+
  • B- ——-B-, B+, AB-, AB+
  • B+——-B+, AB+
  • AB- ——AB-, AB+
  • AB+ ———AB+
91
Q

In both unicellular and multicellular cells, why do they divide? provide 3 reasons

A
  1. Growth and Development: In multicellular organisms, cell division is fundamental for growth and development. It allows organisms to grow from a single fertilized egg (zygote) into a complex structure with trillions of cells. As cells divide, they increase the number of cells, which contributes to the overall growth of the organism.
  2. Repair and Maintenance: Cell division is essential for repairing and maintaining tissues. When cells are damaged due to injury or wear and tear, new cells are produced to replace the damaged or dead ones. This is particularly important in tissues that are frequently subject to damage, such as skin, blood, and the lining of the gut.
  3. Reproduction: In single-celled organisms, cell division is a means of reproduction. Through processes like binary fission in bacteria or mitosis in eukaryotic single-celled organisms, cell division produces two genetically identical offspring from a single parent cell. In multicellular organisms, a specialized form of cell division called meiosis is responsible for producing gametes (sperm and eggs), which are necessary for sexual reproduction.

Biology 11 (4 decks)

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