Aug 31, 2020 · DNA is formed and replicated only in the cell nucleus. PTS: 1 DIF: Cognitive Level: Remembering 29. What is the risk for the recurrence of autosomal dominant diseases? a. 10% b. 30% c. 50% d. 70% ANS: C The recurrence risk for autosomal dominant diseases is usually 50%. Pathophysiology The Biologic Basis for Disease in Adults and Children 8th Edition 97803235834
At the most basic level, DNA is wrapped around proteins known as histones to form structures called nucleosomes. The histones are evolutionarily conserved proteins that form an octamer of eight histone proteins attached together.
Mar 16, 2021 · •A condensed form of DNA that occurs when the cell is dividing • A structure found within the nucleus that produces subunits of ribosomes • A double membrane that surrounds the nucleus • A cell organelle found in eukaryotic cells that houses the DNA and controls activity within the cell CONCEPT Nucleus 7 Which of the following sources of …
a change in the cell's DNA sequence, either, in protein coding gene or in non-coding DNA such as an enhancer. Describe three ways that mutations occur in an organism. spontaneously, after exposure to a mutagen, inherited from a parent organism. missense mutation.
The region in the cell containing this genetic material is called a nucleoid (remember that prokaryotes do not have a separate membrane-bound nucleus). Some prokaryotes also have smaller loops of DNA called plasmids that are not essential for normal growth.
DNA Organization in Prokaryotes. A cell’s DNA, packaged as a double-stranded DNA molecule, is called its genome. In prokaryotes, the genome is composed of a single, double-stranded DNA molecule in the form of a loop or circle (Figure 1). The region in the cell containing this genetic material is called a nucleoid ...
Matched pairs of chromosomes in a diploid organism are called homologous (“same knowledge”) chrom osomes. Of a pair of homologous chromosomes, one came from the egg and the second came from the sperm.
Homologous chromosomes are the same length and have specific nucleotide segments called genes in exactly the same location, or locus. Genes, the functional units of chromosomes, determine specific characteristics by coding for specific proteins. Traits are the variations of those characteristics.
The DNA is twisted by what is known as supercoiling. Supercoiled DNA is coiled more tightly than would be typically be found in a cell (more than 10 nucleotides per twist of the helix). If you visualize twisting a rope until it twists back on itself, you have a pretty good visual of supercoiled DNA.
The variation of individuals within a species is due to the specific combination of the genes inherited from both parents. Even a slightly altered sequence of nucleotides within a gene can result in an alternative trait. For example, there are three possible gene sequences (alleles) on the human chromosome that code for blood type: sequence A, sequence B, and sequence O. Because all diploid human cells have two copies of the chromosome that determines blood type, the blood type (the trait) is determined by which two versions of the marker gene are inherited. It is possible to have two copies of the same allele on both homologous chromosomes, with one on each (for example, AA, BB, or OO), or two different alleles, such as AB.
The size of the genome in one of the most well-studied prokaryotes, E.coli, is 4.6 million base pairs (which would be approximately 1.1 mm in length, if cut and stretched out). So how does this fit inside a small bacterial cell? The DNA is twisted by what is known as supercoiling. Supercoiled DNA is coiled more tightly than would be typically be found in a cell (more than 10 nucleotides per twist of the helix). If you visualize twisting a rope until it twists back on itself, you have a pretty good visual of supercoiled DNA. This process allows the DNA to be compacted into the small space inside a bacteria.
Useless nucleotide sequences (introns) are removed from the mRNA transcript before it enters the cytoplasm . When translation occurs, only genes (exons) with useful information about the protein are expressed in the protein when it's made.
a mutation in which a sense codon that corresponds to one of the twenty amino acids specified by the genetic code is changed to a chain-terminating codon.
A triplet of nitrogenous bases on three consecutive nucleotides within mRNA that are read as a single 'word when translation occurs. Each codon corresponds with an amino acid via the Genetic Code.
Nucleotides are the building blocks of nucleic acids. The components of DNA nucleotide are phosphate, sugar, nitrogenous base
Most cells of adult mammals spend about 20 hours in interphase; this accounts for about 90% of the total time involved in cell division. Interphase includes G1- the cell grows, carries out basic functions and produces molecules needed to build new organelles and other components it will require if it divides; a cell in G1 may enter a non-dividing stage called G0; S - enzymes replicate the cell's genetic material and repair damaged DNA. As S phase begins, each chromosome includes one DNA molecule. By the end of S phase, each chromosome consists of two identical attached DNA molecules; and G2 phase the cell continues to grow but also prepares to divide prducing the proteins that will help coordinate mitosis. The DNA winds more tightly and this start of chromosome condensation signals impending mitosis. Mitosis and cytokinesis, however, are separate from interphase.
Cell division in eukaryotic cells includes mitosis, in which the nucleus divides, and cytokinesis, in which the cytoplasm divides and daughter cells form. Mitosis occurs in four phases, called prophase, metaphase, anaphase, and telophase.
mutations drive evolution because they introduce new alleles to a gene pool, which leads to the emergence of new geneotypes and phentypes. The also increase variation within a species and increase its likelihood of survival
During DNA replication, a complementary strand of DNA is made from each original DNA strand. Thus, if a portion of the original strand is CCT AGC, then the new strand will be
answer choices. before a cell divides, to ensure that the DNA will fit into the resulting cells. during cell division, to ensure that the DNA will fit into the resulting cells. after a cell divides, to provide each of the two resulting cells with a complete sets of DNA instruction.
answer choices. Figure A is an animal cell under anaphase because it forms a cleavage furrow in between the daughter cells. Figure A is an animal cell under anaphase because it forms a cell plate in between the daughter cells.
DNA replication results in two semi-conservative strands of DNA.
A molecule of mRNA is directing the production of tRNA.
The offspring develop from a parent’s fertilized egg.
The homologous chromosomes are preaparing for crossing over.
Erwin Chargaff- Determined that DNA contains equal amounts of adenine and thymine and of guanine and cytosine.
4. The ribosome moves down the mRNA by one codon, and a tRNA carrying the third amino acid comes into place.
Transcription factors- Occurs at initiation of transcription. Match each type of RNA with its correct description. mRNA- Product of transcription that encodes for a protein. tRNA- "bilingual" molecule that binds to an mRNA codon and to an amino acid. rRNA- Structural component of the ribosome.
3. RNA polymerase separates from the DNA and the newly synthesized RNA is released.
Arrange the events of transcription in the order that they occur, beginning with the first event at the top.
DNA always contains the same sugar in its nucleotides.
Not all cells need all proteins encoded in the genome.
What is true of the second DNA molecule? answer choices. It is identical or nearly identical to the first DNA molecule. The sequence of bases, from top to bottom, is opposite the sequence in the first DNA molecule. It is half the size of the first DNA molecule. It is twice the size of the first DNA molecule. Tags:
Enzymes link together to form a template for a new DNA molecule to be built. Enzymes split the DNA molecule into two strands and then transport corresponding nitrogenous bases to each strand. Enzymes link adjacent nucleosides together, becoming an integral part of the structure of the new strands of DNA. Tags: