A duplicated chromosome remains tightly paired with its partner at a region called the
centromere
Before a cell divides, it copies all of its chromosomes. While the two copies of a chromosome are attached they are called
sister chromatids
DNA and protein together form a complex called
chromatin
Chromosomes contain most of the cell's ___________________ which acts as the molecule of heredity.
DNA
The DNA of every eukaryotic cell is stored in one or more ____________ located in the _______________
chromosomes; nucleus
When are the chromosomes of a cell duplicated?
before a cell divides
In sexually reproducing multicellular organisms, the main functions of mitosis are _____.
1. tissue repair/replacement of damaged cells
2. growth and development
Which events occur during prophase?
1. chromosomes condense and are attached to spindle fibers
2. the nuclear envelope breaks down
cytokinesis ___________
finishes mitosis by dividing the cytoplasm and organelles of the original parent cell into two separate daughter cells
During ___________, the cell carries out its normal functions and the chromosomes are thinly spread out throughout the nucleus.
interphase
Looking through a light microscope at a dividing cell, you see two separate groups of chromosomes on opposite ends of the cell. New nuclear envelopes are taking shape around each group. The chromosomes then begin to disappear as they unwind. You are witne
telophase
In a human, which of the following could be identified by the use of a karyotype?
Klinefelter syndrome, where a male has two X and one Y chromosome
Gorillas have 48 chromosomes. How does the number of chromosomes in a gorilla sperm compare with that of a human sperm?
Gorilla sperm have one more chromosome than human sperm
The function(s) of meiosis is/are _____.
reproduction (production of gametes)
Looking through a light microscope at a cell undergoing meiosis, you see that the chromosomes have joined into XX-shaped tetrads. These tetrads are lined up along a plane that runs through the center of the cell. This cell is in _____.
meiosis I
Meiosis starts with _____ cells and produces _____ gametes.
diploid; haploid
Meiosis is typically accomplished in _____.
three steps. All of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes.
The _____ separate in meiosis I; the _____ separate in meiosis II.
homologous chromosomes; sister chromatids
Of the two process, which is going on in my hand right now?
mitosis
If you look through a microscope at a cell and see chromosomes lined up, two by two, what stage of cellular reproduction are you looking at?
meiosis I
What structure is represented by a waist where he is joined to his twin?
centromere
Imagine you found a hypothetical organism with a gamete of 5 chromosomes. How many chromosomes will a cell contain just before mitosis begins?
10
Your 28 year old friend is pregnant. Which of the following screenings is she most likely to initially have to test for Down syndrome?
blood test
How is the fetal DNA used in this new screening tool unique?
It is not from a cell, but is floating freely in the mother's blood
Which of the following is true regarding this new fetal DNA test?
A decreased number of false positive tests for both Down syndrome and Trisomy 18
Which of the following best summarizes current research on this new fetal DNA test?
It works well for finding errors in chromosome number
Which of the following statements apply to the variation in human skin color?
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Which of the following statements accurately describes melanin's function?
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Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?
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Human populations in low-UV environments tend to have more lightly pigmented skin. One explanation is that the selective pressure for dark skin decreases as UV intensity decreases. At the same time there is selection for lighter skin to absorb more UV rad
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Based on the risk factors discussed in the video, which of the following groups would be most likely to develop the bone disease rickets?
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In what way does natural selection depend on the specific environment in which an organism lives?
...
Which of the following is necessary for cancer to begin in a person?
a mutation in a person's DNA
Which of the following is true?
a specific gene can be involved with the development of more than one type of cancer
Which of the following is most likely to happen if a developing embryo lacks integrin?
the embryo will be unable to stay attached to the uterine wall
You are an oncologist trying to invent a drug that prevents tumors from creating their own blood supply. What are you looking to stop?
angiogenesis
A person would be born with webbed hands and/or feet if which of the following failed to happen?
apoptosis
What process involving cell division results in daughter cells that are NOT identical to the parent cell?
sexual reproduction
During which phase of the cell cycle are the chromosomes duplicated?
interphase
Which of the following is the correct sequence of events during mitosis?
Nuclear membrane dissolves, chromosomes line up, chromosomes split, nuclear membrane forms
How does cytokinesis occur in a dividing animal cell?
by the formation of a cleavage furrow
A zygote (i.e., a fertilized egg) undergoes development to grow. What mechanism is used to generate more cells?
mitosis
Like mitosis, meiosis involves duplication of the chromosomes before division starts. However, there are __________ rounds of cell division during meiosis and __________ during mitosis.
two; one
What is crossing over?
the exchange of pieces of homologous chromosomes
What is the chromosome abnormality that causes Down syndrome?
A nondisjunction results in a person with an extra copy of chromosome 21
Genetics studies the inheritance of:
genes
Genes are located on:
chromosomes
Genes come in alternate forms called
alleles
When copies of alleles are the same it is called
homozygous
when copies of alleles differ it is called
heterozygous
the expressed allele si called
dominant
the unexpressed allele is called
recessive
Imagine that, in grinches, cats, eye color is controlled by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele
dominant to
What is the name of the syndrome that produces the XXY combination of sex chromosomes?
Klinefelter syndrome
How many chromosomes would be found in the karyotype of a Down syndrome female?
47