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54 Cards in this Set

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What is the basic structure of DNA?
Deocyribose (Sugar), Phosphate, and Nitrogen Base.
What are the Purines of DNA?
Adendin and Guanine (double ringed)
What are the Pyrimidines?
Cytosine and Thymine (single ringed)
Does Thyamine exist in RNA?
No, Thyamine is repliced by Uracil?
What did Gregor Mendel contribute to genetics?
Characteristics are demtermined by genes (studied pea plants).
What did Thomas Hunt Morgan contribute to genetics?
Chromosomes
What did Feulgen discover?
Nuclear DNA resitricted to chromosomes and that amount of DNA is constant from somatic cell type to cell type, but half as much as in germ cells (egg and sperm).
Do Purines=Pyrimidines?
Only A=T (and will ALWAYS be equal) but the numbers may change throughout different species.
Who discovered DNA structure in 1953?
J.D. Watson & Francis H. Crick.
What conclusions did Crick and Watson make about DNA?
1. DNA is a double stranded molecule
2. DNA is a helical
3. Two strands of DNA are antiparallel (3-5', 5-3')
4. Two strands held together by hydrogen bonds
5. A is always paired w/T (2 H bonds)
C is always paired w/G (3 H bonds)
Define DNA polymerases
The building of new DNA in the 5' to 3' direction. DNA polymerases is a template driven enzyme.
What does DNA ligase do?
DNA ligase joins short single stranded segments together
What does Primase do?
Primase joins RNA nucleotides to make RNA primer
What does the Helicase do during DNA replication?
The Helicase unzips the helix at replication fork.
How is the leading strand built in DNA replication?
DNA polymarse builds the strand in a continuous fashion.
How is the lagging strand constructed in DNA replication?
It is built in segments as the replication forks continue to to unzip the DNA.
What is the job of a single-stranded bindding protein?
It stabilizes unzipped DNA during replication.
What is the role of a Primer in DNA replication?
A primer is about ten nucleotides long (forming a polynucleotide)that attaches to a single-stranded DNA molecule. After this is in place DNA polymerase can add DNA nucleotides to the single-stranded DNA molecule.
Okazaki fragments are also known as what?
Short lagging strand segments.
Mitosis is what kind of divisional process?
Conservative
Meiosis is what kind of divisional process?
Reductive
How is DNA organized into Cells?
By Chromosomes (filaments segaments of DNA w/associated protiens).
How many prokaryotic chromosomes are there?
One.
What are the characteristics of a prokaryotic chromosome?
1. Single, Circular Strand of DNA
2. Naked w/few associated protiens (no histones)
3. Plasmids (extra chromosomal material)
What are the characteristics of a eukaryotic chromosome?
1. Multiple, linear segments of varying length
2. Each segment carries only a protein of genetic message
3. Proteins (histones) associated with DNA
What is a histone?
It is a protein with DNA wrapped around it. The DNA is stabalized by a linker histone protein.
Eukaryotic cells can be haploid only, true or false?
False, eukaryotic cells can by both hapliod and diploid.
Eukaryotic Haploid Complement
DNA occurs in Unpaired segments
Eukaryotic Diploid Complement
DNA occurs in paired segments
What is a Telomere?
Tslomeres are the ends of an eukaryotic chromosome. These contain no genes but short nucleotides (6-10) sequences that repeat 100 to 1000 times.
What is Telomerase?
Telomerase is an enzyme that catalyzes the lengthening of telomeres. They are not present in most somatic cells but in some cancer cells and tissue culture cell lines.
How many alleles are there in any gene?
There are a maximum of two alleles for any particular gene in the human body.
List the steps of Mitosis.
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
List the steps of Meiosis.
1. Interphase
2. Prophase I
3. Metaphase I
4. Anaphase I
5. Telophase I & Cytokinesis
6. Interkinesis
7. Prophase II
8. Metaphase II
9. Anaphase II
10. Telophase II
Describe the process of Interphase.
The DNA first becomes uncoiled and is then translated into proteins. First the DNA uncoils and then becomes translated into proteins. Next the DNA replicates. During this stage there is a nuclear membrane present as well as a nucleolus.
Describe the process of Prophase.
The DNA begins to condense and appears in its replicated form. The Nucleoli start to disappear. The chromatids are attached by centromeres and the centrosomes begin to move away from each other.
What is prometaphase?
Prometaphase comes before metaphase and after prophase. The Nuclear Membrane disappears and the microtubles of the spindle apparatus begin to attache to the kinetochore.
Describe the process of Metaphase.
Chromosomes line up idependently at an equilateral plate (in the form of tetrahydes).
Describe the process of Anaphase.
The centromeres seperate. The genetically identical chromosomes move to opposite poles.
Describe the process of Telophase.
A new nuclear membrane forms. Chromosomes begin to uncoil and the nucleolus reappears. Finally, cytokensis begins to occur.
Describe the process of
Cytokinesis.
The cytoplasm begins to divide. Eukaryotic - cell division. Prokaryotic - cell plate formation.
Describe the process of Prophase I.
The nucler memberan and the nucleoli disappear. The DNA condenses and tetrads are formed (through the process of synapsis). Crossing over occurs and the chromosomes begin to move away from each other.
Describe the process of
Metaphase I.
Tetrads line up on the equatorial plate. The Homologous chromosomes do not migrate independently as they do in mitosis.
Describe the process of Anaphase I.
***THIS IS THE REDUCTION DIVISION***
Tetrads separate, homologous chromosomes migrate to opposite poles. Sister chromatids do NOT separate.
Describe the process of Telophase I and Cytokinesis.
Chromosomes have reached the poles, each polar region contains 1/2 the original # of chromosomes, and the division of cytoplasm.
What is the Nature of the Genetic Code?
1. Linear two dimensional code
2. Code is translated into three dimension structure of proteins
What is the Flow of Genetic Information in the cell?
DNA (transciption) to RNA (translation) to Protein
What are the three types of RNA?
1. rRNA=ribosomal
2. mRNA=messenger
3. tRNA=transfer
What are the three properties of RNA?
1. Single Stranded
2. Sugar = Ribose
3. Uracil instead of Thymine
Name two unique characteristics of RNA?
RNA can replicate itself w/o protein enzymes and displays catalytic activity.
What is the Singlet Code?
1. 4 words (G,C,A,T)
2. 4(1)= 4 words
What is the Doublet Code?
1. 16 Words (AA,CC,AC, etc.)
2. 4(2)= 16 words
What is the Triplet Code?
1. 64 Words (AAA,CCC,ACG, etc.)
2. 4(3)= 64 words
What are the three properties of the code?
1. The Code is universal
2. Code is degenerate (more than one code can select for a specific amino acid
3. Code must be able to select twenty different amino acids