Biology Chapter 14 Questions
Which piece of DNA would move the fastest in gel elctrophoresis? A segment 100, 1000, 5000, or 100000 base pairs long
100
What if the genetic abbreviation of a male human
46, XY
A man who is not colorblind and a woman who is a carrier of the disorder have a son. What is the probability that their son will be colorblind
50%
What percentage of human sperm cells carry and X chromosome
50%
Why is the ratio of male to female births roughly 50:50
Half of all sperm cells carry a Y chromosome
The ________ ____________ ______________ was a 13 year international effort to sequence all 3 billion base pairs in human DNA and identify all human genes. The projected was completed in ______________. The researchers identified __________ in widely separated strands of DNA. They used "__________ ___________", which uses a computer to match DNA base sequences
Human Genome Project 2003 markers shotgun sequencing
Why is a person who has the genotype XXY a male, even though he has two X chromosomes in his cells
Regardless of how many X chromosomes are in the cell, the person will be male if there is a Y chromosome present
___________ _____________ cut DNA into smaller pieces. called ____________ __________ which ares several hundred bases in length. Each restriction enzyme cuts DNA at a different sequence of bases
Restriction enzymes Restriction fragments
What is the tool or technique used and the outcome for: Cutting DNA
Restriction enzymes cut DNA molecules into precise pieces, called restriction fragments, that are several hundred bases in length -smaller fragments of DNA
How are the X and Y chromosomes different
They Y carries fewer genes than the X
What happens to the CFTR gene in individuals who have cystic fibrosis
Three bases are deleted, causing one amino acid to be missing
Bioinformatics would not have been possible without _____________. ________ ____________ is a technology that made the Human Genome Project possible. The markers that the researchers of the Human Genome Project used were ___________ ____________
computers DNA sequencing base sequences
What is trisomy
condition that results from nondisjunction in which an individual is born with 3 copies of a chromosome instead of 2
Since the 1970s, techniques have been developed that allow scientists to __________, __________, and _________ DNA base-by-base. Using these tools, scientists read the _______ _________ in DNA from any cell
cut, separate, replicate base sequences
What is the role of restriction enzymes in studying the human genome
cutting larger DNA molecules into smaller pieces
What is a Barr body
dense region in the nucleus formed by switching off most of the genes in one of the x chromosome
What are SNPs
differences in a base between two individuals
In a pedigree: A shaped that shaded represents a person who _______ the trait. A marriage in a ________ line. A connnection between parents an offspring is _______________. A female is a _______ and a male a _______________. A shape that isn't shaded in represents someone who _________ express the trait
expresses horzontal line connected two shapes vertical line connected to a horizontal connecting siblings circle, square does not
There is a ________ reason for genetic disorders. A change in DNA can alter an __________ _________________ sequence, which can change a protein and therefore, the phenotype. Some common inherited disorders result from a change in __________
molecular amino acid DNA
A colorbind boy's mother must or must not carry the gene for colorblindness?
mother-yes
Why don't males have Barr bodies
their single x chromosome is still active
Inheritance patterns in humans: What does this mean and give an example: Codominance and multiple alleles
there is more than 2 alleles for a particular trait and 2 can both be expressed because on might not be completely domiant over another. **The blood group (ABO) trait is determined by a gene with 3 alleles- IA, AB, and i. The alleles IA and IB are codominant so both of alleles can be expressed
The Icelandic people have always placed high importance on knowing about their ancestors. In fact 80% of all the Icelandic people who have ever lived can be added to a family tree. Medical records are just as detailed. the population is quite isolated, so the gene pool is considered to be homogeneous. Why would these conditions make the genome of the Icelandic population ideal for studying rare inherited disorders associated with gene sequencing errors
these conditions would make the genome of the Icelandic population ideal for studying rare inherited disorders associated with gene sequencing errors because the genomes of the people are similar or pretty much the same. Therefore, it is easier to find base pairs or DNA sequences for disorders because they would stick out. Also, scientists would be able to keep track of who had and didn't have certain disorders because the Icelandic people are aware of their ancestors and medical records
In karyotypes how are the chromosomes that make up each numbered pair similar
they have similar shapes and sizes (some may also carry the same genes, but not necessarily same alleles)
How many human genetic disorders are known
thousands
What were the goals of the Human genome Project
to sequence all 3 billion base pairs of human DNA, identify all human genes, sequence the genomes of model organisms to interpret human DNA, develop techonology to support the research, explore gene functions, study variation , and train future scientists
What is the definition and outcomes in genotype and phenotype of nondisjunction
An error in meiosis in which homologous chromosomes fail to separate(means not coming apart); 3 copies of chromosome 21; Down syndrome-characterized by mild to severe retardation and a high frequency of certain birth defects
Which of these pairs of genotypes result in the same phenotype A) IAIA and IAIB B) IBIB and IBi C) IBIB and IAIB D)IBi and ii
B) IBIB and IBi
Why are the sex chromosomes considered homologous, even thought they vary in size and appearance
Because one sex chromosome was inherited from one parent, and the other was inherited from the other parent
Inheritance patterns in humans: What does this mean and give an example: Sex-linkage
Certain genes are located on certain sex chromosomes making certain traits more common in males vs females or vice versa. Genes found on the Y chromosome are only found and expressed in males. Recessive alleles for genes of x chromosomes are more common among males. **Three genes for color vision are all located on the x chromosome. Colorblindess is a recessive trait so 2 recessive alleles be present in 2 copies on each of the x chromosomes to be expressed in females. In males a defective alleles for any of the genes results in colorblindess because it only has 1 x chromosome and 1 allele for the gene; more common in males than females
Explain why the father of a girl who is colorblind must also be colorblind
Colorblindess is a recessive trait and the color vision gene is located on the x chromsome. 2 recessive alleles have to be present in order for the individual to possess that trait. Males only need one because their other chromosome is a Y that doesn't contain any genes for color vision. Females have 2 X chromosomes one from each parent. You need two recessive alleles so she inherited an allele for colorblindess from both parents. Since males only need 1 recessive allele to be colorblind and the girl recieved one from the father, he must also be colorblind
Steps to explain how genetic disorders have a molecular basis: 1) A gene's _______ sequence changes 2) The ____________ _________sequence that alters a protein changes 3) A change in ________ results
DNA amino acid phenotype
-______________ ____________, most often a result of three copies of chromosome 21 -___________ syndrome, a female with a single X chromosome -__________ syndrome, a male with an extra X chromosome
Down sydrome turner's Klinefelter's
What is the tool or technique used and the outcome for: Reading DNA
Dye-labeled nucleotides are used to make a complementary strand of DNA. Each time a labeled nucleotide is added to the strand, DNA replication stops. Because each base was labeled with a different color, the results is color-coded DNA fragments of different lengths. when gel electrophoresis is used to separate the fragments, scientists can read the DNA sequence directly from the gel -color-coded DNA fragments of different lengths and they're then separated and the order of colored bands on the gels tells the exact sequence of boxes in the DNA
Is a cat with two colors of spots more likely to be male or female
Female; the gene that controls the color of coat spots is located on the X chromosome. In male cats with just one x chromosome they can have spots of only one color. Females can have an allele for orange spots on one x chromosome and an allele for black spots on another. In cells in certain parts of the body, some x chromosome can be switched off. These switches of on and off on the x chromosome can result in orange and black spots
What is the tool or technique used and the outcome for: Separating DNA
Gel electrophores is used. The DNA fragments are put into wells on a gel. An electric voltage moves them across the gel. Shorter fragments move faster than long fragments. within and hour, or 2, the fragments all separate, each appearing as a band on a gel. -long and short DNA fragments separate into bands on gel (based on size)
___________ ________________ separates different sized DNA fragments by placing them at one end of a porous gel, then applying an electric voltage. The electric charge moves the DNA. Using ______-________________ nucleotides, scientists can stop replication at any point along a sing DNA strand. The fragments can then be separated by size using gel electrophoresis and "read:, _______ by _________
Gel electrophoresis dye-labeled base by base
How might the allele that causes a disease stay in the population if it is fatal to those who have the disease
It makes the heterozygote resistant to a fatal disease
Most of the genetic disorders you have learned about are the results of a change in DNA sequence, as with cystic fibrosis, or the presence of an extra chromosome, as with Klinefelter's syndrome. The exception is Turner's syndrome. Women with turner's syndrome only have 45 chromosomes. They are missing an X chromosome. This disorder is the only case in which a person can survive with one less chromosome. What does this tell you about how genetic information is inherited in humans
It tells me that humans can't survive without having at least 1 X chromosome. That means that most of our genetic information is probably carried by the x chromosome
If malaria were eliminated from a certain area, how do you think the frequency of the sickle cell allele in that area would change
It would decrease because people who are heterozygous for sickle cell disease would have an allele that wouldn't be beneficial anymore
A male with the disorder __________________ inherits one extra chromosome. The law that protects people from being discriminated against because of information learned in genetic tests is called the ______________________. A boy who is colorblind inherited the disorder from his ___________. A _________ is a diagram that follows the inheritance of single gene through several generations of a family
Klinefelter's Syndrome Genetic Information Nondiscrimination Act mother pedigree
If a male has two X chromsomes and a Y, what type of abnormality is is and how might it have occured
Klinefelter's syndromes-3 chromosomes on position 23 caused by nondisjunction of sex chromosomes during meisosis
The field of bioinformatics combines both life sciences and modern technology. What are some similarites and differences
Life Science- observations, experiments, hypotheses Information Science-statistics, computer modeling, and data bases Both- Data analysis, visualizations, predictions
Why are all X linked alleles expressed in males even if they are recessive
Males only have 1 X chromosome; the other is a Y
Human genes follow the same __________ patterns of inheritance as the genes of other organisms: -Many humans follow a pattern of ________ ___________ -The alleles for many human genes display a __________ inheritance -Many human genes, including the genes for blood group, have _________ ___________
Mendelian simple dominance codominant mulitple alleles
What causes some human genetic disorders
Nondisjunction, the failure of chromosomes to separate during meiosis, can cause human genetic disorders
What two kinds of enzymes are used in sequencing DNA and what does each enzyme do in the process
Restriction enzymes:cut even the longest DNA molecule into precise pieces called restriction fragments, that are several hundred bases in length. Each restriction enzymes cuts DNA at a different sequence of nucleotides DNA Polymerase: is an enzyme that copied DNA. Single stranded DNA fragments are placed in a test tube containing DNA polymerase. DNA polymerase uses the unknown strand as a template to make one new strand of DNA after another
Why is it helpful to sequence many human genomes, instead of just one
Scientists can find how the human genome varies
Why might it be incorrect to assume that if one chromosome is larger than another the larger chromosome has more genes
Some chromosomes are larger than others because they might have larger stretches of repeating DNA. The smaller chromosome can have more densely packed genes. The repeating DNA in the larger chromsomes doesn't code for proteins, so it doesn't contain genes. In this instance the smaller chromosome would actually have more genes than the larger chromsome
Why does a female with one h allele have normal blood clotting but a male with one h allele has hemophilia
The female still inherited the domiant allele H for normal blood clotting on the other x chromosome. the male with the one h allele has hemophilia because it only has 1 x chromosome and a Y. there is no gene for hemophilia on the y chromosome so the recessive trait is expressed
Why are individuals who are heterozygous for the cystic fibrosis allele unaffected by the disease
The make enough of a particular protein to allow their cells to work properly
How does studying the human genome help us draw conclusions about the inheritance of traits
There are different patterns of inheritance including a pattern of simple dominance, codominance, and multiple alleles, and sex linkage. Also, pedigrees help to learn about patterns of inheritance
Compare and contrast Turner's and Klinefelter's syndrome
Turner's-only occurs in females; individual inherites only 1 X chromosome Klinefelter's-only occurs in males; individual inherites an extra x chromosome Both-results of nondisjunction; individual who has syndrom are unable to reproduce
How do we study the human genome and what have we learned so far
Using tools that cut, separate, and then replicate DNA base by base, scientists can now read the base sequences in DNA from any cell
Inheritance patterns in humans: What does this mean and give an example: Simple Dominance
When at least dominant allele is present the individual expresses the dominant trait for the phenotype. When the individual has 2 recessive alleles the recessive trait is expressed in the phenotype. **The Rh group: when at least 1 Rh+ allele is present the individual has Rh+ blood because its dominant. When 2 Rh- alleles are present the individual will have Rh- because it has 2 recessive alleles
All human cells carry at least one ______ chromosome. the complete set of genetic information an organisms carries in its DNA is its ___________
X genome
From what is karotype made
a photograph of cells in mitosis
What advantage do individuals with one sickle cell allele have
a stronger resistance to malaria
In humans, single base differences occur at how many sites
about 3 million
Humans have 22 pairs of ____________. The cause of Down syndrome is __________ during meiosis. Humans have 3 billion base pairs in their ___________. the new field of ___________ resulted from the Human genome Project
autosomes nondisjunction genome bioinformatics
By using tools that cut, separate, and then replicate DNA, scientists can now read the _________ sequence in DNA from any cell. Restriction enzymes cut pieces of DNA sometimes called restriction __________. Each restriction enzyme cuts DNA at a different sequence of _____________
base fragments nucleotides
The Human Genome Project identified genes associated with many diseases and disorders. From the project came the new science of ___________, the creation and use of databases and other computing tools to manage data. Bioinformatics launched __________, the study of whole genomes
bioinformatics genomics
How does the cell "adjust" to the extra X chromosome in female cells
by randomly switching off most of the genes in one of the x chromosomes
The smaller the DNA, the ________ and farther it moves during gel electrophoresis. After chemically dyed bases have been incorporated into a DNA strand, the order of colored __________ on the gel reveals the exact sequence of bases in DNA
faster bands
what does "shotgun sequencing" do
find overlapping areas of DNA fragments
The human genome project pinpointed __________ and associated particular sequences in those genes with numerous diseases and disorders. It also found that the DNA of all humans matches base-for-base at most sites, but can vary at _______ million sites. The ________ ________ __________, launched in 2008, will catalogue the variation among 1000 people
genes 3 1000 genomes project
A _________ is the full set of all the genetic information that an organism carries in its DNA. Chromosomes are bundles of DNA and protein found in the nucleus of eukaryotic cells. A __________ is a picture that shows the complete diploid set of human chromosomes, grouped in pairs and arranged in order of _________ size. A typical human diploid cell contains ________ chromosomes or _______ pairs
genome karyotype decreasing 46, 23
Some alleles that cause disease in the homozygote can provide an advantage in the ___________. The __________ associations between sickle cell disease and malaria and between cystic fibrosis and typhoid demonstrate how the heterozygous state reduces the risk of ___________
heterozygote geographic infection
what is the term used to describe the pair of chromosomes in each numbered group on karyotypes Which ones are the autosomes
homologous chromosomes 1-22
What happens when an individual has trisomy 18
individual has Down Syndrome- which is often characterized by mild to severe mental retardation and a high frequency of certain birth defects
How did the DNA sequence of the allele that causes cystic fibrosis different from that of the normal allele
it is missing 3 DNA bases or 1 amino acid, compared to that of the normal allele
Compared with normal hemoglobin, the hemoglobin of a person with sickle cell is ________ _________
less soluble
Sometimes, during meiosis, homologous chromosomes fail to separate. The ____________ (not coming apart) can create a gamete with an abnormal number of chromosomes, leading to offspring with ___________ or ________ chromosomes
nondisjunction missing or extra
what forms a Barr body
one of the X chromosomes in a female cell
A circle represents a female in a _________. The protein that cuts DNA into pieces is a restriction ___________. An inherited disorder that appears more often in males than females is probably caused by a ____________. The 23 pairs of human chromosomes are arranged from largest to smallest in a __________
pedigree enzyme sex-linked gene karyotype
A chart used to analyze the pattern of inheritance that shows the relationships in a family is a ___________. They can be used to determine the nature of genes and alleles associated with ________ human traits
pedigree inherited
The enzyme that copies DNA is DNA ____________. Bacteria produce restriction enzymes that cut the _______ molecule into smaller pieces. Restriction fragments are always cut at a particular sequence of ______________. The technique that separates differently sized DNA fragments is _________ ___________.
polymerase DNA nucleotides gel electrophoresis
what did scientists in the Human Genome Project look for in DNA to identify the locations of genes
promoters
To identify genes, they found __________, exons, and other sites on the DNA molecule. to locate and identify as many _____________(collections of linked single-base differences) in the human population as possible, the International HapMap Project began in 2002.
promoters haplotypes
Two of the 46 chromosomes are the __________ _____________ that determine an individuals sex: _______= female and ______=male. The X chromosome carries nearly _____ times the number of genes as the Y chromosome. The other 44 are __________, or autosomal chromosomes
sex chromosomes XX, Xy 10 autosomes
A gene located on a sex chromosome is a ___________-__________ __________. The genes on sex chromosomes show a sex-linked pattern of inheritance, since females have _______ copies of many genes(located on the X chromosome) while males have just one. In females, most of the genes in one of the X chromosomes are __________ in each cell
sex-linked gene 2 inactivated
-__________ _________ disease, in which a defective polypeptide makes hemoglobin in the blood less soluable. -________ ________ in which a deletion of three bases in a gene causes cell membrane to lose their ability to transport chloride ions -____________ disease,in which a single codon for a certain amino acid repeats more than 40 times, causing mental deterioration and uncontrolled movements
sickle cell cystic fibrosis Huntington's
The inherited disease in which hemoglobin molecules clump into long fivers, changing the shape of blood cells is ___________
sickle cell disease
If nondisjunction occurs during meiosis what happens to gametes
some gametes may have an extra copy of some genes
People who are heterozygous for sickle cell disease are generally healthy because they have what?
some normal hemoglobin in their red blood cells
