Which of the following statements cannot be inferred from the karyotype shown?
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The cell contains DNA.
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The cell contains 46 chromosomes.
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The cell is diploid.
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The cell is prokaryotic.
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Eukaryotic DNA is found wrapped around histones to form nucleosomes, which further compact and ultimately form linear chromosomes. The prokaryotic genome is found as a loop and in eukaryotes as a double-stranded linear structure.
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The DNA in both organisms is wrapped around the nucleosomes in a compact structure. The eukaryotes show a loop structure and prokaryotes show a double-stranded linear genome.
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The genetic material shows ringed heterochromatin structure. The prokaryotes show multiple loops, and eukaryotes show a condensed chromatin.
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In both organisms genetic material is wrapped around histones. The prokaryotes have a condensed structure in nucleoids, but eukaryotes have double-stranded linear structure.
Which of the following statements about structure 1 on the karyotype is not true?
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Structure 1 consists of homologous chromosomes.
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The two parts of structure 1 will have genes in different loci.
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The two parts of structure 1 originate from different parents.
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The two parts of structure 1 will have slightly different sequences of nucleotides.
Based on the karyotype provided, the nondisjuction of which chromosome causes Down syndrome?
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chromosome 21
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chromosome 22
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X chromosome
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Y chromosome
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anaphase - metaphase - prophase - cytokinesis
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anaphase - prophase - metaphase - cytokinesis
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prophase - anaphase - metaphase - cytokinesis
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prophase - metaphase - anaphase - cytokinesis
The two graphs show the results of a study on a cancer drug. The left graph shows the results control group, untreated cancer cells. The right graph shows the results for the cells treated with the drug.
Which option describes how this drug is likely to work?
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It intervenes with cellular growth.
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It intervenes with DNA replication.
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It intervenes with formation of mitotic spindles.
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It intervenes with cytokinesis.
In a study on cell division, researchers culture synchronously dividing human cells with thymidine. This causes the cells to arrest at the boundary. The cells are then placed in medium lacking thymidine, which releases the block, and the cells begin to divide again. Starting with Sample A and ending with Sample D, the DNA content of the cells is measured at different times after thymidine is removed. Results for four samples (A-D) are shown in the graph. Explain what is happening in terms of the cell cycle and DNA content in sample B.
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All the contents of the cell have been doubled.
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The DNA content of the cell has doubled.
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Two cells have been fused.
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The cells are showing the semiconservative mechanism of cell division.
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- cell cycle progression
- p53
- p21
- CHK2
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- p53
- p21
- CHK2
- cell cycle progression
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- p21
- p53
- CHK2
- cell cycle progression
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- CHK2
- p53
- p21
- cell cycle progression
The insulin growth factor (IGF-1) promotes cell proliferation as shown in the diagram. The expression of which protein in the diagram is controlled through negative feedback?
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active Cdk4
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Cyclin D1
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Cyclin D1/Cdk4 complex
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IGF-1
This graph shows the p53 protein expression and the percentage of survivors over time for people who had prostate cancer. The red line shows people with normal functioning p53 protein. The blue line shows people with p53 protein that does not function well.
What conclusion can we draw from this graph?
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p53 protein have no effect on cancer.
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Having functional p53 protein decreases the chances of recurring cancer and increases survival.
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Having abnormal p53 protein decreases the chances of recurring cancer and increases survival.
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p53 protein may increase or decrease the chnces of recurring cancer based on other factors.