Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MED 109- BIOLOGY II > 8. LOCATING GENES ALONG CHROMOSOMES > Flashcards

8. LOCATING GENES ALONG CHROMOSOMES Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q
  1. What are Mendel’s “Hereditary Factors” known as nowadays?
A
  • genes
  • Mendel did not know about the existence of genes or
    chromosomes when he conducted his experiments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q
  1. What is a gene locus?
A
  • this is the location of a particular gene on a
    chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q
  1. What technique can we use to see the specific locus of a gene on a chromosome?
A
  • we can tag the isolated chromosomes
  • they would be tagged with a fluorescent dye
  • this dye highlights the gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  1. Provide 2 fundamental characteristics of genes?
A
  1. Each gene is a long DNA molecule
    • it consists of several nucleotides
  2. Each gene carrier information
    • for the synthesis of a specific protein
    • it carries this information in its nucleotide sequence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
  1. How many genes does one chromosome have?
A
  • every chromosome has over 1000 genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  1. What are Homologous Chromosomes (Homologs)?
A
  • these are the chromosome pairs found during
    Meiosis I
  • they carry the same genes
  • they may carry different alleles of those genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. Where are the chromosomes that make up a Homologous Pair inherited from?
A

IN EACH PAIR:
- one homologous chromosome is inherited from the
father
(this is known as the paternal homolog)
- the other homologous chromosome is inherited from
the mother
(this is known as the maternal homolog)

THIS MEANS THAT:
- one allele is inherited from the father
- one allele is inherited from the mother

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. What does the Chromosomal Theory of Inheritance state?
A
  1. Genes have specific positions on chromosomes
    • these are known as their Loci
  2. Chromosomes undergo segregation
    • this is also known as Chromosomal Separation
    • this separation during meiosis accounts for Mendel’s
      Laws of Segregation and Independent Assortment
  3. Chromosomes undergo Independent Assortment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  1. What does Mendel’s Law of Segregation state?
A
  • the two alleles for each gene separate during gamete
    formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  1. What does Mendel’s law of Independent Assortment state?
A
  • the alleles of genes on Non-Homologous
    chromosomes will assort independently
  • this happens during gamete formation

NB:
- this law does not apply to linked genes
- it does not apply to genes on the same chromosome
- these genes are usually positioned very close to each
other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  1. Are genes inherited?
A
  • no
  • the chromosomes that carry the genes are inherited
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  1. Who was Thomas Hunt Morgan?
A
  • he came up with the Chromosomal Theory of
    Inheritance
  • this states that genes are located on chromosomes
  • these chromosomes are then inherited
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  1. What did Thomas Hunt Morgan run his experiments on?
A
  • fruit flies
  • these experiments provided evidence that genes are
    located on chromosomes
  • genes can also be referred to as:
    “Mendel’s Heritable Characteristics”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  1. Why are Fruit Flies a convenient organism for Genetic Studies?
A
  • they breed at a high rate
  • a generation can be bred every 2 weeks
  • they have only 4 pairs of chromosomes
    (this makes the genetics very easy to follow)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  1. What exactly did Thomas Hunt Morgan observe with relation to the fruit flies?
A
  • Morgan observed wild type phenotypes that were
    common in the fruit fly populations
  • these were considered the normal phenotypes
  • Morgan also observed alternative traits
  • these were considered mutant phenotypes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  1. Thomas Hunt Morgan mated white-eyed male flies with red-eyed female flies.
    What were his results?
A
  • White eyes are considered a mutant trait
  • Red eyes are considered the normal, wild trait
  • the Fist Filial (F1) Generation all had red eyes
  • the Second Filial (F2) Generation showed a 3:1 red eye
    to white eye ratio
  • only the males had white eyes
17
Q
  1. What did Thomas Hunt Morgan determine through his experiment that focused on fly eye colour?
A
  • the allele for Red eyes was the dominant allele
  • the White-eyes mutant allele must be located on the X
    Chromosome
  • this means that eye colour for these flies is a X-linked
    condition

NB:
- this experiment supported the Chromosomal Theory
of Inheritance

18
Q
  1. What can be found in humans and other mammals with regards to genetics?
A
  • there is a Chromosomal Basis of Sex Determination
  • there are 2 different types of sex chromosomes
  • there is a larger X chromosome
  • there is another smaller Y chromosome
19
Q
  1. Are X and Y chromosomes the same?
A
  • NO
  • they are different
  • they are non-homologous
  • ONLY THE ENDS OF THE Y CHROMOSOME:
    • have regions that are homologous with the X
      chromosome
20
Q
  1. How many genes do the X and the Y chromosomes have in common?
A
  • 18 genes
21
Q
  1. What is the genotype for females?
A
  • XX
22
Q
  1. What is the genotype for males?
A
  • XY
23
Q
  1. What does each ovum contain?
A
  • each ovum contains only an X chromosome
24
Q
  1. What does each sperm contain?
A
  • a sperm can contain either an X or a Y chromosome
  • 50% of sperm carry an X chromosome
  • 50% of sperm carry a Y chromosome
25
Q
  1. What can be said about the genes found on the sex chromosomes?
A
  • sex chromosomes have genes for many characters
  • these characters are unrelated to sex
26
Q
  1. What is a sex-linked gene?
A
  • this is a gene located on either X chromosome
27
Q
  1. What does the term “Sex-Linked” refer to in humans?
A
  • it refers to a gene on the X Chromosome
  • this is known as an X-Linked gene
  • this is because the Y Chromosome carrier very few
    genes
  • this means that there are very few Y linked disorders
    present
28
Q
  1. How many genes does an X chromosome roughly have?
A
  • 1 100 genes
29
Q
  1. How many genes does a Y chromosome have?
A
  • 78 genes
30
Q
  1. What do Sex-Linked genes follow?
A
  • they follow specific patterns of inheritance
31
Q
  1. What genotype is necessary for a recessive Sex-Linked Trait to be expressed?
A

A FEMALE:
- needs 2 copies of the recessive allele

A MALE:
- needs only 1 copy of the allele
- this is because the Y Chromosome cannot counteract
the mutant gene

32
Q
  1. In which gender are sex-linked recessive disorders much more common?
A
  • males
33
Q
  1. Link 3 examples of X-Linked Recessive Disorders?
A
  1. Haemophilia
  2. Colour Blindness
  3. Duchenne Muscular Dystrophy
34
Q
  1. What three types of Sex-Linked Disorders can an individual have?
A
  1. X-Linked Recessive Disorders
  2. X-Linked Dominant Disorders
  3. Y-Linked Disorders

MED 109- BIOLOGY II (90 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions