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134 Cards in this Set

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  • Back
An adjective that describes an organism and is also a characteristic of the organism is a ____.
trait
When purely tall plants are crossed with purely short plants, the offspring are all ____.
hybrid
An organism that is hybrid for a certain trait has what kind of genes?
one dominant gene and one recessive gene
A human male carries which two sex chromosomes?
XY
A visible characteristic of an organism can also be called a ___.
phenotype
How many total chromosomes do human body cells contain in each nucleus?
46
How many chromosomes would the human sex cells, sperm or egg, contain?
23
What is the genotype for a female’s two sex chromosomes?
XX
What is Gregor Mendel's nickname?
"Father of Genetics"
List two resons why Mendel chose pea plants.
convenience, 7 traits on one plant, can self-fertilize, easy to cross-pollinate
What is the difference between dominant and recessive alleles?
Dominant genes are stronger than recessive. In a heterozygote,dominant genes determine the phenotype and the recessive gene has no noticeable effect.
What us the probability that an offspring will inherit the dominant gene from a parent that is hybrid for that trait?
50%
When two hybrids are crossed, what is the genotypic ratio?
1:2:1
Be able to draw this.
When two hybrids are crossed, what is the phenotypic ratio?
3:1
Be able to draw this.
Can a short plant ever be a hybrid? Explain why or why not.
no, Shortness in pea plants is recessive; two short alleles must be inherited (tt).
When would the recessive gene be expressed phenotypically?
when two recessive alleles are inherited
Name three functions of ordinary cell division that produces two genetically identical daughter cells.
cell replacement, organism growth, and asexual reproduction
What is the difference between sexual and asexual production?
Sexaul requires a male and a female (2 parents) and asexual only requires one.
Where is the DNA located in a eukaryotic organism?
in the nucleus
What are sister chromatids?
two identical parts of a duplicated chromosome, containing identical genes and connected at a centromere
What is the orderly sequence of events that extend from the time a cell first arises until it divides?
cell cycle
Most of the cell cycle is spent in which phase?
interphase (90%)
Why is it difficult to see individual chromosomes during interphase?
They are in the form of very long, thin strands called chromatin.
The amount of DNA in a cell would double during ____.
S phase of interphase OR between G1 and G2
Which two phases of mitosis are essentially opposite in terms of changes in the nucleus?
prophase and telophase
If an intestinal cell of a dog contains 78 chromosomes, then a dog sperm cell would contain ____ chromosomes.
39
Tumors that remain at their site of origin are called ___, while tumors from which cells migrate to other body tissues are called ____.
benign; malignant
A fruit fly somatic cell contains 8 chromosomes. This means that ___ different combinations of chromosomes are possible in its gametes.
16
2n=8, so n=4
______ is to somatic cells as haploid is to ______.
diploid; gametes or sex cells
If a single diploid cell with 18 chromosomes undergoes meiosis to produce sperm, the result will be ____ sperm, each with ____ chromosomes.
4; 9 (haploid)
What event occurs during Prophase I of meiosis that contributes to genetic recombination and variety?
crossing over
How does the karyotype of a human female differe from a human male?
The female kayotype will have XX at the 23rd pair and the male will have XY.
How does mitosis conserve the chromosome number while meiosis reduces it by half?
In mitosis, a single replication of the chromosome is followed by one division of the cell. There are two cell divisions in meiosis.
What is a somatic cell?
a body cell
What is fertilization?
the combination of the haploid sperm cell nucleus with the haploid egg cell nucleus, resulting in a zygote
What is conception?
the moment of fertilization
Describe cytokinesis.
it is the division of the cytoplasm forming two separate daughter cells. occurs during any telophase.
Which type of cancer arises in the bone or muscle?
sarcomas
Cancers that originate in the skin or linings of the intestine are called ___.
carcinomas
Where do lymphomas and leukemias form in the body?
in blood-forming tissues like bone marrow and lymph nodes
Name four ways to prevent cancer.
don't smoke
exercise
avoid overexposure to the sun
high-fiber, low-fat diet
get regular exams
If a cancerous body part receives high-energy electromagnetic waves to disrupt cell division, then that form of therapy is called ___.
radiation
What is chemotherapy?
a treatment for cancer in which drugs are administered to disrupt cell division
When do the chromatin fibers coil so that you can see the chromosomes with a light microscope?
prophase
What else happens during prophase?
nucleolus disappears, sister chromatids are joined at the centromere, mitotic spindle forms, centrosomes move away from one another, spindle forms as microtubles grow out from centrosomes, and nuclear envelope (membrane) disappears
What event occurs during Prophase I of meiosis that contributes to genetic recombination and variety?
crossing over
How does the karyotype of a human female differe from a human male?
The female kayotype will have XX at the 23rd pair and the male will have XY.
How does mitosis conserve the chromosome number while meiosis reduces it by half?
In mitosis, a single replication of the chromosome is followed by one division of the cell. There are two cell divisions in meiosis.
What is a somatic cell?
a body cell
What is fertilization?
the combination of the haploid sperm cell nucleus with the haploid egg cell nucleus, resulting in a zygote
What is conception?
the moment of fertilization
Describe cytokinesis.
it is the division of the cytoplasm forming two separate daughter cells. occurs during any telophase.
Which type of cancer arises in the bone or muscle?
sarcomas
Cancers that originate in the skin or linings of the intestine are called ___.
carcinomas
Where do lymphomas and leukemias form in the body?
in blood-forming tissues like bone marrow and lymph nodes
Name four ways to prevent cancer.
don't smoke
exercise
avoid overexposure to the sun
high-fiber, low-fat diet
get regular exams
If a cancerous body part receives high-energy electromagnetic waves to disrupt cell division, then that form of therapy is called ___.
radiation
What is chemotherapy?
a treatment for cancer in which drugs are administered to disrupt cell division
When do the chromatin fibers coil so that you can see the chromosomes with a light microscope?
prophase
What else happens during prophase?
nucleolus disappears, sister chromatids are joined at the centromere, mitotic spindle forms, centrosomes move away from one another, spindle forms as microtubles grow out from centrosomes
What occurs during metaphase?
mitotic spindle is fully formed, centromeres line up in the middle of the cell, spindle microtubles are attached to each sister chromatid and begin pulling toward the opposite poles
What occurs during anaphase?
sister chromatids of each chromosome separate and are now called daughter chromosomes, microtubules shorten as the daughter chromosomes are pulled toward opposite poles. the cell elongates as the microtubules not attached to centromers lengthen.
What occurs during telophase?
two groups of chromosomes have reached the cell poles and the reverse of prophase occurs
When does cytokinesis occur and what happens?
usually occurs druing telophase. a division of the cytoplasm begins and a cleavage furrow forms. the cell pinches in two forming two daughter cells.
How is prophase I in mitosis different from prophase I in meiosis?
homologous chromosomes stick together in pairs, so you have 4 chromatids called a tetrad. crossing over occurs.
How is meiosis I different from mitosis?
In meiosis I, two haploid cells form and chromosomes are still double
What is independent assortment?
the alleles of different gene pairs assort independently of each other during meiosis so that random combinations end up in the gametes
What happens if there are 3 chromosomes at chromosome pair #21?
Trisomy 21 condition also known as Down syndrome.
What are chiasmata?
the site where crossing over has occured between chromatids of homologous chromosomes during prophase I of meiosis
Where does meiosis occur?
in the testes or ovaries where gametes are produced
Describe the process of nondisjunction.
it is an accident of mitosis or meiosis where a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase
Can a cell have more than two sex chromosomes?
yes, but it usually causes some kind of syndrome
What is a wild-type trait?
a trait that is the prevailing one in nature phenotypically
Genes are carried on ____.
chromosomes
The cell cycle results in
2 diploid cells with the same genetic info in the same amounts
What is the order of the cell cycle stages?
interphase, prophase, metaphase, anaphase, telophase
A cell that completed the cell cycle WITHOUT undergoing cytokinesis would ___.
have two nuclei.
How many autosomes do humans have?
44 (non-sex chromosomes)
Both mitosis and meiosis are preceded by ____.
interphase
DNA and RNA are polymers of ______ monomers.
nucleotide
The backbone of DNA consists of ______.
a repeating sugar-phosphate-sugar-phosphate pattern
RNA contains ______, whereas DNA contains ______.
uracil; thymine
Who discovered the structure of DNA?
Watson and Crick
In a DNA double helix, adenine pairs with ______ and guanine pairs with ______.
thymine; cytosine
During replication, ______ what joins the nucleotides of a new DNA strand together?
DNA polymerases
What is transcription?
the synthesis of RNA on a DNA template
What is Beadle and Tatum's modern version of the "one gene, one ____?"
polypeptide
How many nucleotides are in a codon?
three
How many amino acids are common to all living things?
20
The region of DNA where RNA synthesis begins is the ______.
the promoter
What is the ultimate source of all diversity and evolution?
mutations and genetic recombinations
What is a phage?
a virus that infects bacteria
Where does translation occur?
ribosomes
Which reproductive cycle would allow a virus to make more of its own kind and not kill the host cell?
lysogenic cycle
Name an emerging virus.
West Nile, hantavirus, SARS, Ebola, HIV, new flu viruses
What is an emerging virus?
recently appeared or recently come to the attention of medical scientists
What is an example of a herpes virus?
chicken pox, shingles, cold sores(herpes simplex), roseola, and genital herpes
Why are emerging viruses so dangerous?
b/c of their potential to spread globally to people groups that have no history with them. due to affordable international travel, increased IV drug use, blood transfusion technology, and sexual promiscuity, viral outbreaks do not remain localized. p. 193
What virus causes AIDS?
HIV
Rank these words from smallest to largest: codon, chromosome, nucleotide, gene
nucleotide, codon, gene, chromosome
What enzyme does HIV require to convert its RNA genome into a DNA version?
reverse transcriptase
What is a mutagen?
a natural or human-made (chemical or physical) agent that interacts with DNA and causes a mutation...mustard gas, derivitives of preservatives, radiation....
Can mutagens cause cancer?
yes
Most genes come with alternate forms of ___.
alleles
What are the 4 blood types?
A, B, AB, O
When can amniocentesis be performed?
between weeks 14 and 20 of pregnancy
What is the gentoype for an individual that is heterozygous for free earlobes?
Ee
What is the name given to the specific location of a gene on a chromosome?
a locus
Give examples of homozygous genotypes.
AA, bb, cc, DD, tt, MM
Give examples of heterozygous genotypes.
Nn, Tt, Ww, Yy
What % of heterozygous offspring will occur with parents BB crossed with bb.
100%
A couple has seven children, all boys. What is the probability that their next child will be male?
50%
What is the sign the you are dealing with incomplete dominance?
the phenotypic result of the heterozygote is in between the two homozygotes
What is the condition called when there is a progressive weakening and loss of muscular tissue, usually in males?
muscular dystrophy
How can two organisms that have different genotypes for a trait be identical in phenotype?
one can be purebred dominant and the other is hybrid; both would have the dominant allele for the trait and that's all it takes to show up phenotypically
Red-green color blindness and hemophilia are two human genetic disorders that are caused by a(n) _____.
sex-linked gene
The passing of traits from parents to offspring is called ____.
heredity
Human height, eye color, and skin color are all traits controlled by ____.
polygenic inheritance
______ is the branch of biology that deals with the study of heredity.
genetics
____ _____ deals with manipulating the arrangement of DNA, like moving fragments of DNA from one organism and inseritng them into another.
genetic engineering
What separates during meiosis?
alleles
What controls traits in organisms?
genes
What term describes the inheritance of cystic fibrosis?
recessive genes
What are some areas in which advancements in genetics would be important?
agricultural, health, and medicine
What are some benefits of genetically engineered crops?
increased crop production pest resistance
Explain why a trait inherited by incomplete dominance is not a blend of two alleles.
The two alleles are present in the offspring and can be passed on. Their DNA remains separate; it does not mix.
Explain why offspring may or may not resemble either parent.
There are many genes and combinations, so an individual may look similar or very different from either parent.
What is the purpose of a pedigree?
it is a visual tool to trace a trait through generations of a family
What should you expect if two pink (RW) flowers are cross-pollinated? Use a Punnett square to find out.
25% red, 50% pink, and 25% white
Whatis another word for heterozygous?
hybrid
What is another word for true-breeding?
pure or homozygous
How could two brown-haired parents have a blonde-haired child?
both could be carriers or heterozygous/hybrid for the brown hair, yet pass on the recessive gene to their child (bb).
What is the scientific name for the pea plant that Mendel experimented with at the monastery?
Pisum sativum
What phase are cells in if they are not in mitosis?
interphase