Finals Review Flashcards
What are the basic steps of replication?
- The opening of the double helix and separation of the DNA strands
- The priming of the template strand
- The assembly of the new DNA segment
What is the role of the helicase?
To unwind the strands of DNA
What is the role of the primer?
It shows the polymerase where to create the strand
What is the role of polymerase?
It creates the formation of a particular polymer, especially DNA or RNA
What is the role of ligase?
It brings out the ligation of DNA or another substance
Guanine pairs with?
Cytosine
Cytosine pairs with?
Guanine
If guanine makes up 25% of the bases in a DNA double helix, what percent do the rest make?
In this case, 25% each (whatever percentage A-T, C-G MUST be the same percentage)
What type of bond links the nitrogenous based together from opposing strands?
Hydrogen bonds
What are histones?
“Spools” of proteins that the DNA strands wrap around inside chromosome
What are mutations?
When a DNA gene is damaged or changed in such a way as to alter the genetic message carried by the gene
What is the semi conservative model of DNA replication?
One strand of each molecule is parental (old) and the other is new. (the 2 strands will never see each other again)
What is a gene?
The basic unit of heredity passed from a parent to a child
What are Okazaki fragments?
Short strands of DNA that link together to create one
Is DNA usually double stranded or single stranded?
Double stranded
During transcription, what is the template and what is the product?
Template: DNA
Product: mRNA
What is the role of mRNA?
It carries information
What is the role of tRNA?
It delivers amino acids to ribosome during translation
What is the role of rRNA?
It joins with proteins to form intact ribosomes
What is the role of RNA polymerase?
It adds nucleotides to the end of a growing RNA strand
Is RNA usually double stranded or single stranded?
Single stranded
During transcription, which RNA nucleotide pairs with DNA’s adenine?
Uracil
What is gene expression?
The appearance in a phenotype of a characteristic or effect attributed to a particular gene
Where does translation take place?
Cytoplasm
What is a codon?
A sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule
What is an exon?
A code for proteins
What is an intron?
Noncoding
What is deletion?
A type of mutation in which one or more nucleotides are lost in DNA
What is substitution?
A type of mutation in which a single base pair changes
What is insertion?
A type of mutation in which one or more nucleotides are added
Are mutations in exons or introns more likely to result in an altered protein?
Exons
Are mutations permanent or temporary changes in the DNA sequence?
Permanent
Hershey and Chase
Discovered DNA is hereditary material
Rosalind Franklin
Used X-ray crystallography to study DNA structure
Watson and Crick
Discovery of DNA double helix
Erwin Chargaff
Discovered the relationship between DNA bases
What are HeLa cells? Where did they come from? What kind of cells are they? Why are they used?
They are cells from a lady who had cancer. They were used without her consent and are used for the polio vaccine, virus research, and cancer research
What are the cells cycle stages? Which stage is specifically part of mitosis?
Interphase, Prophase, Metaphase, Anaphase, and Telophase
What is a karyotype?
Image of an individual complement of chromosomes arranged by size, length, shape, and centromere location
What chromosome pairs are assigned female?
X,X
What chromosome pairs are assigned male?
X,Y
What is the total number of chromosomes in humans?
46
What is an autosome?
Paired chromosomes with the same length, shape, centromere location, and genes
What is a sex chromosome?
Members of a pair of chromosomes that differ between males and females
What is nondusjunction, and when does it occur?
When chromosomes fail to separate. It happens in meiosis
In which stage of the cell cycle is DNA replicated?
S phase
What is Down syndrome caused by?
An extra chromosome
What is Marfans syndrome?
A genetic condition that affects the body’s connective tissue
What part of the DNA might be the only physiological barrier to immortality?
Telomeres
What is an oncogene?
Any gene that helps transform a normal cell into a tumor cell
What is a tumor suppressor?
A type of gene that makes a protein
What is a tumor?
An uncontrollable growth resulting in an abnormal accumulation of cells
What is cancer?
Uncontrollable growth of cells that can invade other tissues and organs
What does benign mean?
Non cancerous
What does malignant mean?
Cancer
What does homozygous mean?
Having identical alleles of a gene
What does heterozygous mean?
Having two different alleles of a gene
What is a genotype?
The particular set of alleles carried by an individual
What is a phenotype?
An individuals observable traits
What is a dominant trait?
Allele that masks the affects of a recessive allele on the homologous chromosome
What is a recessive trait?
Allele with an effect that is masked by dominant allele
Shaded square
Affected male
Shaded circle
Affected female
Clear square
Non affected male
Clear circle
Non affected female
Shape that is half shaded and half clear
Carrier
What is a mono hybrid cross?
A cross in which individuals with different alleles of a gene are crossed
What is a codominance?
Inheritance pattern in which the full and separate phenotype effects of two alleles are apparent in heterozygous individuals
How do X- linked disorders work?
Male must inherit only one allele to be affected by the disorder a female must inherit two
What is a polyploidy trait?
Having three or more of each type of chromosome characteristics of the species
What is a polygenic trait?
A pattern of inheritance in which multiple genes affect one trait
