Genetics Flashcards
(108 cards)
1
Q
What is sexual reproduction?
A
A process where genetic information from two organisms combines to produce genetically different offspring.
2
Q
What are gametes?
A
Reproductive cells produced by the father and mother, specifically sperm and egg cells in humans.
3
Q
What is the diploid number of chromosomes in human cells?
A
46 chromosomes.
4
Q
What is the haploid number of chromosomes in human gametes?
A
23 chromosomes.
5
Q
What happens at fertilization?
A
A male gamete fuses with a female gamete to produce a fertilized egg, or zygote.
6
Q
What is a zygote?
A
A fertilized egg that contains a full set of chromosomes, making it diploid.
7
Q
What process does a zygote undergo to develop into an embryo?
A
Cell division by mitosis.
8
Q
How does an embryo inherit characteristics from its parents?
A
It receives a mixture of chromosomes (and therefore genes) from both the mother and father.
9
Q
Where are male gametes found in flowering plants?
A
In the pollen.
10
Q
Where are female gametes found in flowering plants?
A
In the ovaries at the bottom of the stigma.
11
Q
What is meiosis?
A
A type of cell division that produces gametes and does not create identical cells.
12
Q
Where does meiosis occur in humans?
A
In the reproductive organs (ovaries and testes).
13
Q
What happens to DNA before a cell undergoes meiosis?
A
The DNA duplicates to ensure there is enough for each new cell.
14
Q
True or False: Meiosis produces identical cells.
A
False.
15
Q
Fill in the blank: Gametes are _______ cells.
A
haploid.
16
Q
A
17
Q
What does the zygote develop into after mitosis?
A
Embryo
The zygote undergoes mitosis to develop into an embryo.
18
Q
From whom does the embryo inherit characteristics?
A
Both parents
The embryo receives a mixture of chromosomes (and therefore genes) from its mother and father.
19
Q
What type of cell division produces gametes?
A
Meiosis
Meiosis is distinct from mitosis as it does not produce identical cells.
20
Q
Where does meiosis occur in humans?
A
Reproductive organs
Specifically, meiosis occurs in the ovaries and testes.
21
Q
What happens to the DNA before a cell starts to divide in meiosis?
A
It duplicates
This duplication ensures there is enough DNA for each new cell.
22
Q
What is the outcome of the first division in meiosis?
A
Chromosomes line up in pairs and are pulled apart
Each new cell receives one chromosome from each pair.
23
Q
What is created when chromosomes are mixed during meiosis?
A
Genetic variation
Mixing up the genes is important for creating diversity in the offspring.
24
Q
What happens during the second division of meiosis?
A
Chromatids are pulled apart
This division results in four haploid daughter cells.
25
How many gametes are produced at the end of meiosis?
Four
## Footnote
Each gamete has a single set of chromosomes and is genetically different.
26
What are the male gametes in flowering plants called?
Pollen
## Footnote
The male gametes are found in the pollen grains.
27
Where are the female gametes located in flowering plants?
Ovaries at the bottom of the stigma
## Footnote
The female gametes are produced in the ovaries.
28
True or False: Each arm of an X-shaped chromosome is an identical copy of the other arm.
True
## Footnote
This is true before the cell starts to divide.
29
Fill in the blank: In humans, meiosis only occurs in the _______.
Reproductive organs
30
31
What does the zygote develop into after cell division?
An embryo
## Footnote
The embryo inherits characteristics from both parents.
32
What type of cell division produces gametes?
Meiosis
## Footnote
Meiosis occurs in the reproductive organs (ovaries and testes).
33
How does meiosis differ from mitosis?
Does not produce identical cells
## Footnote
Mitosis produces identical cells while meiosis creates genetic variation.
34
What happens to DNA before meiosis begins?
It duplicates
## Footnote
This ensures there is enough DNA for each new cell.
35
What do the chromosomes do during the first division of meiosis?
Line up in pairs
## Footnote
One chromosome in each pair comes from the mother and one from the father.
36
What is created after the first division in meiosis?
New cells with one copy of each chromosome
## Footnote
Each new cell has a mixture of chromosomes from both parents.
37
Why is mixing genes during meiosis important?
It creates genetic variation
## Footnote
Genetic variation is crucial for evolution and adaptation.
38
What occurs during the second division of meiosis?
Chromosomes line up again and chromatids are pulled apart
## Footnote
This division is similar to mitosis.
39
How many haploid daughter cells are produced at the end of meiosis?
Four
## Footnote
Each gamete has a single set of chromosomes.
40
Where are male gametes found in flowering plants?
In the pollen
## Footnote
Female gametes are found in the ovaries at the bottom of the stigma.
41
Fill in the blank: The arms of the chromosomes in meiosis are called _______.
Chromatids
## Footnote
Chromatids are pulled apart during the second division.
42
True or False: In humans, meiosis occurs in all body cells.
False
## Footnote
Meiosis only occurs in the reproductive organs.
43
44
What is the main function of DNA?
Passing on your DNA to the next generation
## Footnote
DNA carries all the instructions for your characteristics.
45
What are the repeating units that make up DNA strands?
Nucleotides
## Footnote
DNA strands are polymers made up of lots of repeating units called nucleotides.
46
What are the three components of a nucleotide?
Sugar molecule, phosphate molecule, base
## Footnote
Each nucleotide consists of one sugar molecule, one phosphate molecule, and one base.
47
What forms the sugar-phosphate backbone of DNA?
Sugar and phosphate molecules
## Footnote
The sugar and phosphate molecules in the nucleotides form a 'backbone' to the DNA strands.
48
What are the four different bases found in DNA?
* A (adenine) * T (thymine) * C (cytosine) * G (guanine)
## Footnote
One of four different bases joins to each sugar in a nucleotide.
49
What is the shape of a DNA molecule?
Double helix
## Footnote
A DNA molecule has two strands coiled together in the shape of a double helix.
50
What is complementary base pairing in DNA?
A pairs with T, and C pairs with G
## Footnote
Each base links to a base on the opposite strand in the helix.
51
What type of bonds join the complementary base pairs in DNA?
Weak hydrogen bonds
## Footnote
The complementary base pairs are joined together by weak hydrogen bonds.
52
Where are chromosomes found in eukaryotic cells?
In the nucleus
## Footnote
Chromosomes are long, coiled up molecules of DNA found in the nucleus of eukaryotic cells.
53
What is a gene?
A section of DNA on a chromosome that codes for a particular protein
## Footnote
The sequence of bases in the gene determines what protein is produced.
54
What makes up an organism's genome?
All of an organism's DNA
## Footnote
The complete set of genetic material in an organism is referred to as its genome.
55
Fill in the blank: DNA strands are made up of repeating units called _______.
Nucleotides
56
True or False: A always pairs with C in DNA.
False
## Footnote
A always pairs with T, and C always pairs with G.
57
Fill in the blank: The sugar and phosphate molecules in DNA alternate to form a _______.
Backbone
58
What is the role of the sequence of bases in a gene?
Determines what protein is produced
## Footnote
The specific order of bases encodes the information required for protein synthesis.
59
What is the structure of a DNA double helix?
Two strands coiled together in a spiral shape
## Footnote
The double helix structure allows for stability and efficient packing of genetic material.
60
61
What is a gene?
A section of DNA on a chromosome that codes for a particular protein.
62
What determines what protein is produced by a gene?
The sequence of bases in the gene.
63
What makes up an organism's genome?
All of an organism's DNA.
64
What is the first step to extract DNA from fruit cells?
Mash some strawberries and put them in a beaker containing a solution of detergent and salt.
65
What is the purpose of detergent in the DNA extraction process?
To break down the cell membranes to release the DNA.
66
What role does salt play in the DNA extraction process?
It makes the DNA stick together.
67
What should you do after mixing the strawberries with detergent and salt?
Filter the mixture to get the froth and big, insoluble bits of cell out.
68
What happens when you gently add ice-cold alcohol to the filtered mixture?
The DNA starts to come out of solution as it's not soluble in cold alcohol.
69
What does the DNA appear as when it precipitates out of the solution?
A stringy white precipitate (a solid).
70
How can you collect the DNA after it has precipitated?
Carefully fish it out with a glass rod.
71
Who were awarded the Nobel Prize for determining the structure of DNA?
Crick, Watson, and Wilkins.
72
In what year were Crick, Watson, and Wilkins awarded the Nobel Prize?
1962.
73
Fill in the blank: The __________ will break down the cell membranes to release the DNA.
detergent
74
Fill in the blank: The __________ will make the DNA stick together.
salt
75
True or False: DNA is soluble in cold alcohol.
False
76
What can genetic diagrams predict?
How different characteristics will be inherited
77
What are alleles?
Different versions of the same gene
78
What do genes control?
What characteristics you develop
79
How many alleles does an organism have for each gene?
Two versions, one on each chromosome in a pair
80
What does it mean if an organism is homozygous?
It has two alleles for a particular gene that are the same
81
What does it mean if an organism is heterozygous?
It has two alleles for a particular gene that are different
82
How are dominant alleles represented?
With a capital letter (e.g. 'C')
83
How are recessive alleles represented?
With a small letter (e.g. 'b')
84
What determines the characteristic present if an organism has one dominant and one recessive allele?
The dominant allele
85
What is required for an organism to display a recessive characteristic?
Both alleles must be recessive
86
What is a genotype?
The combination of alleles an organism has
87
What is a phenotype?
The characteristics an organism has, determined by its alleles
88
What is monohybrid inheritance?
The inheritance of a single characteristic
89
How can monohybrid inheritance be shown?
Using a monohybrid cross
90
In the example of hamsters, what allele causes superpowers?
The recessive allele 'b'
91
What is the dominant allele for normal hamsters?
The allele 'B'
92
What are the parents' genotypes in the example of hamsters?
BB and bb
93
What is the phenotype of a hamster with the genotype bb?
It will have superpowers
94
What is the phenotype of a hamster with genotype BB or Bb?
Normal and boring
95
What is the offspring's genotype if the parents are BB and bb?
All offspring are Bb
96
What is the ratio of normal to superpowered offspring in the next generation?
3:1
97
What is the probability of normal hamsters in this generation?
75%
98
What is the probability of superpowered hamsters in this generation?
25%
99
Fill in the blank: An organism's _______ determines its traits.
genotype
100
101
How many matched pairs of chromosomes are in every human body cell?
23 matched pairs
## Footnote
The 23rd pair is labelled XX or XY.
102
What chromosomes do males have?
X and Y chromosomes (XY)
## Footnote
The Y chromosome causes male characteristics.
103
What chromosomes do females have?
Two X chromosomes (XX)
## Footnote
The XX combination allows female characteristics to develop.
104
What is the probability of having a male or female child?
Equal chance of 50:50
## Footnote
This probability means that each child has an equal chance of being male or female.
105
What does a genetic diagram show in terms of sex determination?
The results of XX and XY combinations
## Footnote
The diagram demonstrates the probabilities of having male or female offspring.
106
True or False: All eggs have one X chromosome.
True
## Footnote
Sperm can carry either an X or a Y chromosome.
107
Fill in the blank: A sperm can have either an _______ chromosome or a Y chromosome.
X
## Footnote
This determines the sex of the child upon fertilization.
108
What is the relationship between family pedigrees and genetic disorders?
Family pedigrees can show monohybrid inheritance
## Footnote
They help trace genetic disorders through generations.
