DNA Structure & Base Pairing
What are the three components of a DNA nucleotide?
A phosphate group, deoxyribose sugar, and a nitrogenous base.
What is the main purpose of DNA replication before cell division?
To copy DNA so that each daughter cell can receive a complete set of genetic information.
During which major part of the cell cycle does a cell grow, carry out normal functions, and copy its DNA?
Interphase
This occurs when the cell cycle is disrupted and cells divide uncontrollably
What is Cancer?
What has hands but cannot clap?
A clock.
A DNA strand has the sequence A–C–T–G–G–A. What is the complementary DNA sequence?
T–G–A–C–C–T
The specific part of Interphase when DNA replication occurs.
What is S phase (Synthesis)?
A skin cell has 46 chromosomes before DNA replication. How many chromosomes should each daughter cell have after normal mitosis and cytokinesis?
46 chromosomes. Mitosis maintains chromosome number by distributing one complete set to each daughter cell.
The term for programmed cell death used to remove damaged cells
What is Apoptosis?
What gets wetter the more it dries?
A towel.
A sample of double-stranded DNA contains 30% adenine. What percentage is cytosine? Explain.
20%. Thymine is also 30%, leaving 40% for guanine and cytosine, or 20% each.
This enzyme builds the new DNA strand during replication.
What is DNA Polymerase?
The three primary purposes of the cell cycle in multicellular organisms
What is for Growth, tissue repair, and replacing damaged cells?
The structural mass that forms when crowding occurs because cells lack contact inhibition
What is a Tumor?
What did one cell say when its sister stepped on its foot?
Mitosis
Two organisms have DNA containing the same four bases, but they produce different proteins. What difference in their DNA can explain this?
The sequence of bases differs. Different base sequences can provide instructions for different proteins.
Each resulting DNA molecule contains one original strand and one newly made strand. The term that describes this is...
What is semiconservative?
How do mitosis and cytokinesis differ?
Mitosis divides the nucleus and separates duplicated chromosomes. Cytokinesis divides the cytoplasm, producing two daughter cells.
These are when the cell pauses to make sure everything is done correctly before continuing the cell cycle.
What are Checkpoints?
What runs but never walks, has a mouth but never talks?
A river.
A student claims, “The instructions in DNA are stored in its sugar-phosphate backbone.” Briefly explain why this claim is correct or incorrect.
The claim is incorrect. Genetic information is stored in the sequence of nitrogenous bases. The repeating sugar-phosphate backbone supports the molecule but does not encode the instructions.
Scientists label both strands of a DNA molecule. The DNA replicates twice using only unlabeled nucleotides. Of the four resulting DNA molecules, how many contain an original labeled strand? Explain.
Two. The two original strands each remain in one DNA molecule. The other two molecules contain only strands made during the experiment.
Cytokinesis is different in plants and animals because...
Cytokinesis in plants is done by forming a cell plate (New cell wall) between cells
Cytokinesis in animals is done by pinching off cells (cleavage furrow)
This type of tumor stays localized in one place and does not invade other tissues.
Benign
What disappears as soon as you say its name?
Silence.