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11U Biology > Genetics > Flashcards

Genetics Flashcards

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1
Q

What happens in metaphase I?

A

Tetrads migrate to the centre and more genetic dissimilarities are made by random assortment, how pairs line up across the centre of the cell.

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2
Q

Summarize co-dominance inheritance.

A

It involves two alleles, 3 genotypes (ex. BB, BW, WW), and 3 phenotypes (black, black and white, white). Two dominant traits combine to form a mixture of the two alleles, very similar to incomplete dominance.
Ex. If a black cow is crossed with a white cow, the offspring will be black and white.

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3
Q

What is a mutation?

A

The changing of the structure of a gene.

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4
Q

What is a True Breeding Organism?

A

An organism that produces offspring that are genetically identical for one or more traits.

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5
Q

What is the difference between mitosis and meiosis II?

A

Four haploid are formed in meiosis II, and two diploid cells are formed in mitosis.

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6
Q

What type of cells are involved in meiosis and mitosis?

A

Somatic cells (body cells) are involved in mitosis, and gametes (sex cells) are involved in meiosis.

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7
Q

What accounts for the differences between egg and sperm cells?

A

Eggs must be larger so they can contain more nutrients in their cytoplasm needed for cell division, and as the sperm cells need to be able to swim to an egg to fertilize it, so they must be plentiful, small and fast.

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8
Q

How is genetic variation in the gametes achieved during meiosis?

A

By crossing over and random assortment.

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9
Q

What happens in the interphase stage of the cell cycle?

A

DNA replicates and cells prepare for division.

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10
Q

What are homologous chromosomes?

A

A pair of chromosomes (one from each parent) that contain the same genes at the same locations, but can have different forms of that gene.

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11
Q

When does Down Syndrome occur?

A

When a male or female has 3 copies of chromosome #21 (trisomy non-disjunction).

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12
Q

What happens in prophase I?

A

Chromosomes shorten and thicken, nuclear membrane dissolves, homologous chromosomes pair up forming tetrads, and chromosomes exchange DNA in a process called crossing over.

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13
Q

Molecules that have the ability to cut DNA at a specific site are called _________________.

A

Restriction enzymes

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14
Q

Gametogenesis produces sex cells with half the number of chromosomes as a body cell.

A

True

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15
Q

Define hybrid.

A

A hybrid is an offspring resulting from the cross between two true-breeding species.

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16
Q

Explain crossing over.

A

Crossing over occurs when the tetrad of homologous chromosome tangle and exchange pieces of DNA in prophase 1.

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17
Q

Less than ___% of the total genome codes for protein.

A

2%

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18
Q

Describe sex-linked inheritance in regards to hemophilia.

A

As the hemophilia allele is passed on in the X chromosome, females can be normal, a carrier or a hemophiliac (XHXH, XHXh, XhXh). As males only have one X chromosome, they are either normal or hemophiliacs (XHY, XhY).

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19
Q

State the difference between monosomy and trisomy non-disjunction?

A

Trisomy is when there is three homologous chromosomes in the place of a homologous pair, and monosomy is when their is one chromosome in place of a homologous pair.

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20
Q

How many cells are produced from one cycle of meiosis and mitosis?

A

4 cells are produced from meiosis, and 2 from mitosis.

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21
Q

Define diploid.

A

Containing a set of chromosomes, one from each parent.

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22
Q

What is the role of the resulting cells from meiosis and mitosis?

A

Cells resulting from mitosis are the same as the parent cell, and used to create more somatic cells. Cells resulting from meiosis are used to create sex cells for reproduction.

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23
Q

What is the difference between discontinuous and continuous variation?

A

Discontinuous variation is when the inheritance of one gene has no effect on the expression of products of the second gene, and continuous variation is when a phenotype is determined by the interaction of different genes together (ie. skin colour).

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24
Q

Define allele.

A

A particular type of gene (ie. allele for eye colour, hair, etc.)

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25
State the Principal of Dominance.
When individuals with contrasting traits are crossed, the offspring will only express the dominant trait.
26
What are three reasons for cell division?
Tissue repair, replacing dead cells, and growth.
27
What is the chromosome number of a parent cell in mitosis and meiosis?
They are both diploid (2n)
28
What is the function of the cell membrane? [3]
It supports the cell, protects the interior, and controls which substances enter the cell.
29
Functions unknown for more than ___% of the genes discovered.
50%
30
What can a karyotype reveal?
Genetic abnormalities in genes of parents or of child with an unknown disability, the gender of a fetus, and test for certain defects through examination of cells from uterine fluid.
31
What is a chromatin?
An uncoiled strand of DNA
32
What is the difference between genetics and genomics?
Genetics is the study of single genes in isolation and genomics is the study of all genes in the genome and the interactions among them and their environment[s] (or the study of the genome in an organism).
33
What is DNA fingerprinting?
The technique of analyzing DNA fragments. Those fragments form distinct patterns that can be used to identify a person or organism.
34
Summarize incomplete dominance inheritance.
It involves two alleles, 3 possible genotypes (ex. CRR, CWW, CRW), and 3 possible phenotypes (ex. red, pink, white). Two dominant traits combine to form an entirely different trait in the offspring, very similar to co-dominance. Ex. If a red flower is crossed with a white flower, the subsequent offspring will be pink.
35
Explain random assortment.
Random assortment occurs when tetrads of homologous chromosomes migrate to the center of a cell and randomly align across the middle in metaphase 1.
36
How many chromosomes do human body cells usually contain?
46 (23 pairs)
37
What some characteristics of all living things? [8]
Require energy, composed of cells, able to reproduce, require water, respiration, produce waste, growth, able to adapt to environment.
38
What is the Human Genome Project?
A project began in 1990 and completed in 2004 mapping the DNA sequence of the entire human genome.
39
What happens in telophase I?
A nuclear membrane reforms around the new nuclei.
40
What happens in anaphase I?
Homologous chromosomes move to opposite poles, reduction division occurs.
41
Compare and contrast spermatogenesis and oogenesis.
In spermatogenesis, the cytoplasm divides evenly, 4 equal-sized sperm cells are produced, and the cells are significantly smaller. In oogenesis, one daughter cell receives most of the cytoplasm, and the other three polar bodies die, it provides nutrients for cell division after fertilization, and they are 100 times larger than sperm cells. They both produce haploid cells, and are produced by meiosis.
42
In what molecule is genetic information stored?
DNA
43
Define DNA.
DNA is deoxyribonucleic acid, which determines the fundamental and distinctive characteristics of something or someone.
44
When does Turner's Syndrome occur?
When a female has only one copy of the X chromosome (monosomy non-disjunction).
45
What is albinism and what causes it?
Individuals with albinism are unable to produce melanin, which is a pigment found in skin, eye, and hair colour. It is caused by an autosomal recessive allele.
46
Define heredity.
The transmission of characteristics from parent to offspring.
47
What is genetic engineering?
Taking genes from one organism and putting them into another organism to create a transgenic organism.
48
Which chromosome contains the most genes and which contains the least?
Chromosome 1 has the most, and the Y chromosome has the fewest.
49
What happens in anaphase?
The spindle fibres pull the chromosomes to opposite ends of the cell.
50
State the Mendel's Law of Segregation.
Organisms inherit two copies of genes (one from each parent) and only donate one copy of each gene to their gametes because the chromosomes separate during meiosis.
51
What happens in metaphase?
Spindle fibres guide chromosomes to the centre of the cell.
52
Summarize multiple allele inheritance.
It involves 2 or more alleles, and 3 or more genotypes and phenotypes. Think blood types.
53
What is the difference between a dominant and recessive trait?
A dominant trait is one that will always be expressed if present, and a recessive trait is latent (present but not active), unless without a dominant trait to overpower it.
54
What is the name for the circular pieces of DNA that can be used to introduce new genes into an organism?
Plasmids
55
What is chorionic villi sampling? When does it occur?
It occurs as early as eight weeks into pregnancy, and involves removing cells from the chorion, which is the outer layer surrounding the embryo.
56
What are sex cells called?
Gametes
57
What is the function of cytoplasm? [2]
Allows organelles to move around, and creates a chemical environment.
58
Describe sex-linked inheritance.
Females have two X chromosomes, and males have one X chromosome and one Y chromosome. They each pass on one two their offspring, which determines the sex of the child. Genes passed on from the sex chromosomes are called sex-linked inheritance.
59
What is the function of meiosis and mitosis?
The purpose of meiosis is to create genetically identical cells for growth, repair, and maintenance; and the purpose of mitosis is to create genetically different cells through crossing over and random assortment.
60
What is non-disjunction and when does it occur?
Non-disjunction produces gametes with the wrong number of chromosomes and occurs when there is a failure in the separation of the pair of homologous chromosomes during meiosis.
61
Prior to cell division, the original chromosome and the duplicate it is attached to are called __________.
Sister chromatids
62
What is gene therapy?
A procedure by which defective genes are replaced with normal genes to cure genetic disorders.
63
What is the function of the endoplasmic reticulum?
Transports materials through the cell.
64
What is segregation?
The separation of paired alleles during meiosis so that members of each pair of alleles appear in different gametes.
65
What is the function of ribosomes?
They put together proteins.
66
What are some similarities and differences in homologous chromosomes?
They are similar in size and shape and contain the same genes in the same locations, but can have different forms of that gene.
67
Summarize basic monohybrid inheritance.
It involves two alleles (dominant and recessive), 3 genotypes are possible (BB, Bb, bb), and 2 phenotypes are possible (the dominant or recessive trait). Ex. Curly hair is dominant and straight hair is recessive. If two parents are heterozygous, what is their likelihood of producing a child with straight hair? [A= 25%]
68
What is Multiple Marker Screening and when can it be performed?
Multiple Marker Screening can be performed between 15 and 20 weeks into the pregnancy, and it is a blood test that tests for various hormone levels that could be indicative of an increased risk for a particular birth defect.
69
What are some applications of DNA fingerprinting? [4]
- Determining paternity - Criminal investigations - Forensics - Personal identification
70
Define recombinant DNA.
A fragment of DNA made by combining nucleotide sequences that would not be found together naturally.
71
How many genes are in the human genome?
30,000
72
What happens in cytokenesis?
Cytoplasm of the two cells separate in animal cells, a cell wall is formed in a plant cell.
73
How much of the human genome is made up of "junk DNA" (repeated sequences)
50%
74
What is the difference between homozygous and heterozygous?
Homozygous is an individual with two identical alleles (PP or pp), and heterozygous is an individual with two different alleles (Pp).
75
What is muscular dystrophy and what causes it?
Muscular dystrophy is a disease marked by the progressive weakening and wasting of the muscles, and is caused by an abnormal recessive allele on the X-chromosome.
76
What is a karyotype and how is it created?
A karyotype is a genetics test and is created when chromosomes from a cell in metaphase are stained and photographed. The photograph is enlarged and cut up into individual chromosomes, which are then identified and arranged in order of size and examined.
77
Organisms that contain genes from other organisms are considered _____________.
Transgenic
78
What is a centromere?
The constricted region joining the two sister chromatids that make up an X-shaped chromosome.
79
What is a chromosome?
Bundles of tightly-coiled DNA located within the nucleus of a cell.
80
What are the four common types of chromosomal structure changes
Deletion/Insertion (portion of chromosome is deleted or inserted), Duplication (portion of chromosome is duplicated, leading to extra genetic material), Translocation (portion of one chromosome is transferred to another chromosome), and Inversion (portion of chromosome has broken off, turned upside down and reattached).
81
What is the difference between an autosome and an allosome?
An allosome is a sex chromosome and an autosome is any chromosome which is not a sex chromosome.
82
What is the difference between an incompletely dominant trait and a codominant trait?
An incompletely dominant trait is expressed along with another trait (red and white flower produce pink flower), and a codominant trait is expressed as a blending of traits (black and white cow make a cow with black and white spots).
83
Define haploid.
Having a single set of unpaired chromosomes.
84
Define hemophilia.
It is a sex-linked disorder passed on in the X chromosome which impairs the body's ability to induce blood clotting.
85
What are the three types of gene mutations?
Positive, negative and neutral.
86
What is a Pedigree? What does it do?
A Pedigree is a chart of a person's ancestors that can analyze the inheritance pattern of a specific trait.
87
What is the chromosome number of cells that are produced from mitosis and meiosis?
The chromosome number of a resulting cell from mitosis is diploid, and the chromosome number of a resulting cell from meiosis is haploid.
88
What is a genome?
An organisms complete set of DNA.
89
What are the two main ways that genetic disorders can occur?
A change in chromosome structure or a change in chromosome number.
90
What happens in telophase?
The chromosomes reach opposite sides and begin to unwind.
91
What happens in prophase?
Chromatin condenses and thickens, nuclear membrane disappears, and spindle fibres start to form.
92
State Mendel's Law of Independent Assortment.
If genes are located on separate chromosomes, they will be inherited independently from one another.
93
What is a gene?
A piece of chromosome that contains instructions for making protein, and therefore governs the expression of specific traits, made up of many nucleotide base pairs (A, T, C, G).
94
What is the difference between genotype and phenotype?
Genotype refers to the genetic makeup of an individual and phenotype refers to the physical appearance with respect to a specific trait.
95
What is a chromatid?
One half of two identical copies of a replicated chromosome.
96
What is amniocentesis?
A procedure where amniotic fluid is removed from the amniotic sac with the aid of an ultrasound and a long needle. The cells are then tested for genetic disorders.
97
What is a fetoscopy? When does it occur?
A fetoscopy is a procedure performed at 18 weeks to visually examine the fetus. A small video camera is inserted through the abdominal wall into the uterus into the amniotic cavity where the fetus can be viewed.
98
Explain the process of horizontal gene transfer.
The transfer of deoxyribonucleic acid between different genomes.

11U Biology (7 decks)

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