Science genes, DNA and chromosomes unit Flashcards
1
Q
Asexual reproduction
A
An organism makes more of itself without exchanging genetic information with another organism (clone)
2
Q
Sexual reproduction
A
New organisms are created by combining the genetic information from two individuals
3
Q
Gametes
A
An organism’s reproductive cells (egg and sperm)
4
Q
Genetic variation
A
Difference in the genome (hereditary information) amongst members of the same species
5
Q
An organism’s reproductive cells are called gametes. Name two.
A
Egg and sperm
6
Q
Genome
A
Hereditary information
7
Q
Most cells in the human body have 46 chromosomes, which ones only have 23?
A
Female and male chromosomes (egg and sperm)
8
Q
What are Mendel’s three principles?
A
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment
9
Q
Homozygous
A
Same Alleles
10
Q
Heterozyhous
A
Different Alleles
11
Q
Is heterozygous dominant or recessive?
A
- 2 different alleles
- Inherited a different version from each parent
- In a heterozygous genotype, the dominant allele overrules the recessive one
- dominant trait will be expressed.
12
Q
Is homozygous dominant or recessive?
A
- Homozygous dominant if it carries two copies of the same dominant allele
- Homozygous recessive, if it carries two copies of the same recessive allele
- Mainly recessive
13
Q
Nucleus
A
Where chromosomes “live”
14
Q
Chromosomes
A
Contain all the genetic material
15
Q
Where chromosomes “live”
A
Nucleus
16
Q
Contain all the genetic material
A
Chromosomes
17
Q
Gene
A
A segment of a chromosome (made up of DNA)
18
Q
DNA
A
Material from which chromosomes are constructed
19
Q
A segment of a chromosome (made up of DNA)
A
Gene
20
Q
Material from which chromosomes are constructed
A
DNA
21
Q
Homologous chromosomes
A
Matching pairs of chromosomes (located in all cells except gametes)
22
Q
Matching pairs of chromosomes (located in all cells except gametes)
A
Homologous chromosomes
23
Q
How many chromosomes do homo sapiens have?
A
have 46 chromosomes
24
Q
Gene
A
A portion of DNA that determines a certain trait
25
Allele
A specific form of a gene
- Responsible for the variations in which a given trait can be expressed
26
Genetic variation is because of...
Genetic variation is because of alleles - they help us adapt and survive
27
Each chromosome has a...
Each chromosome has a very long molecule of tightly coiled DNA
28
If you stretched the DNA in one cell...
If you stretched the DNA in one cell all the way out, it would be about 2 meters long
29
Stretching all the DNA in your body...
Stretching all the DNA in your body, the resulting strand would be the same length as 150,000 round trips to the moon!
30
What does DNA stand for?
DeoxyriboNucleic Acid
31
The double helix "ladder" of a DNA molecule is held together by what?
The double helix "ladder" of a DNA molecule is held together by "rungs" made of pairs of chemicals called bases
32
What are the four bases?
1. Adenine
2. Guanine
3. Cytosine
4. Thymine
33
How many base pairs in a DNA molecule are there in your body?
There are millions of base pairs in a DNA molecule!
34
What rules do they always follow?
- A always pairs with T
- C always pairs with G
- Genetic code
35
Genetic code
A sequence of 3 DNA bases (base pairs) that code for each amino acid.
36
A sequence of 3 DNA bases (base pairs) that code for each amino acid.
Genetic code
37
How genetically similar are you to a stranger?
99.9% genetically similar
38
What do genes make?
Genes don't make proteins, they make amino acids.
39
Protein
Large, complex molecules that play critical roles in the body
40
Large, complex molecules that play critical roles in the body
Protein
41
What is protein made of?
Is is made of long chains of amino acids.
42
Is is made of long chains of amino acids.
Protein!
43
Different combinations of _ make different _
Different combinations of amino acids make different proteins
44
How many types of proteins are there?
20 types
45
There are 20 types of...
PROTEIN!
46
How are traits made?
Gene - 1 amino acid - DNA sequence - protein that helps pigments = trait
47
When you change the _ that changes the _ and that changes the _
When you change the base (DNA) that changes the amino acid and that changes the protein.
48
Mutation
A mutation is any change in a gene or chromosome
- Phenotype may be different
49
Any change in a gene or chromosome
- Phenotype may be different
Mutation
50
List the types of Gene mutations!
a) Substitution - wrong base is used; this is the most common mutation
b) Insertion - when extra base is added
c) Deletion - when a base is left out
51
Substitution in Gene mutations
wrong base is used; this is the most common mutation
52
Insertion in Gene mutations
when extra base is added
53
Deletion in Gene mutations
when a base is left out
54
What is the most common mutation?
Substitution is the most common mutation
55
Is race a biological reality, encoded in our DNA, or not?
No, it's not
56
List the types of Chromosomal Mutations
- Deletion
- Duplication
- Inversion
- Translocation
57
Why do mutations happen reason 1
1. Random errors
- Substitution, insertion, or deletion of a base
- Example: G-T pairings are a result of substitution
58
Why do mutations happen reason 2
2. Mutagens - any physical or chemical agent in the environment can cause a mutation
Examples: Radiation, asbestos, chemicals in smoke
59
What are the locations of mutations?
Reproductive/Sex cells and Somatic/Body cells
60
Reproductive/Sex Cells
- Does not affect the parent, but the mutation is transmitted to the offspring
61
Somatic/Body cells
- Mutation is not passed to offspring
- Any cells produced from a mutated cell (through cell division) WILL ALSO HAVE THE MUTATION
62
Genetic disorder
A genetic disorder is an abnormal condition that a person inherits through genes or chromosomes.
63
- Does not affect the parent, but the mutation is transmitted to the offspring
Reproductive/Sex Cells
64
- Mutation is not passed to offspring
- Any cells produced from a mutated cell (through cell division) WILL ALSO HAVE THE MUTATION
Somatic/Body cells
65
An abnormal condition that a person inherits through genes or chromosomes.
Genetic disorder
66
A person can be a carrier how?
A person can be a carrier (having one dominant and one recessive allele)
67
A person can be a carrier of a trait or genetic disorder...
A person can be a carrier (having one dominant and one recessive allele) of a trait or genetic disorder without displaying that trait or disorder.
68
Genetic disorders list
- Cystic Fibrosis
- Sickle cell anemia
- Hemophilia
- Down Syndrome
- Tumor suppressor gene mutations
69
What is the relationship between genes, chromosomes and DNA?
- Work together to make you who you are
- Chromosomes carry DNA in cells
- DNA is responsible for building and maintaining your human structure
- Genes are segments of your DNA, which give you physical characteristics that make you unique
70
Harmful mutations
An organism may not be able to survive or reproduce (albanism, not enough melanin pigment)
71
Neutral mutations
Changes to the phenotype that do not affect adaptation nor reproduction (eye colour)
72
Beneficial mutations
An organism has increased chances of surviving and/or reproducing (being able to camoflauge in nature or being lactose tolerant)
73
An organism may not be able to survive or reproduce (albanism, not enough melanin pigment)
Harmful mutations
74
Changes to the phenotype that do not affect adaptation nor reproduction (eye colour)
Neutral mutations
75
An organism has increased chances of surviving and/or reproducing
Beneficial mutations
76
Advantages of sexual reproduction
Genetic diversity
77
Advantages of asexual reproduction
Takes less time and requires only one parent
78
Disadvantages of sexual reproduction
Takes more time and requires two parents
79
Disadvatages of asexual reproduction
No genetic diversity
80
How does the genetic code lead to the expression of a phenotype?
DNA holds the instructions, or blueprint, for making proteins in its sequence of nucleotides. The process of transcription copies a specific segment of the genetic instructions, a gene, into a sequence of nucleotides of an RNA molecule. The RNA serves as an intermediate or messenger that takes the genetic information to the ribosome for translation into a sequence of amino acids that form a protein molecule. A protein performs a specific function inside or outside of the cell that makes it.
81
What is the law of dominance?
- in a heterozygote, one trait will conceal the presence of another trait for the same characteristic
- Rather than both alleles contributing to a phenotype, the dominant allele will be expressed exclusively
82
What is the law of segregation?
- Genes come in different versions, or alleles
- A dominant allele hides a recessive allele and determines the organism's appearance
- When an organism makes gametes, each gamete receives just one gene copy, which is selected randomly
83
What is the law of Independent Assortment?
- the alleles of two (or more) different genes get sorted into gametes independently of one another
- In other words, the allele a gamete receives for one gene does not influence the allele received for another gene
