Bio 100 Unit #2 Flashcards
This is the function of tRNA.
tRNA transports amino acids to the ribosome during protein synthesis.
What is a codon and what molecule has them?
A codon is a sequence of 3 nucleotides on mRNA that codes for an amino acid.
What 2 pyrimidines are found in RNA?
cytosine and uracil
What can be found in an RNA nucleotide?
1 phosphate
1 Ribose sugar
1 nitrogen base: either A, U, G or C
When during the cell cycle is DNA copied?
S phase of interphase
What happens during ANAPHASE of mitosis?
Sister chromatids are pulled apart.
What is chromatin?
Loosely coiled DNA found in the nucleus of a cell in interphase, thus NOT dividing.
What are ribosomes made of?
RNA - specifically rRNA
How many chromosomes are found in a body cell? Gamete?
46 in body cells
23 in gametes such as sperm or egg cells
What kind of cells undergo mitosis?
Body cells, like muscle or skin cells, undergo mitosis.
How are DNA & RNA polymerase the same and different?
Both are enzymes used to unzip DNA. DNA polymerase also adds DNA nucleotides during replication. RNA polymerase adds nucleotides for transcription.
How many chromosomes are found in a normal karyotype?
46 total: 44 autosomes and 2 sex chromosomes
What is the longest phase of the cell cycle?
Interphase
What phase of mitosis overlaps with cytokinesis?
Telophase
What are sister chromatids?
Identical copies of DNA that are held together by a centromere. They can be seen during cell division.
What DNA bases are complimentary to:
AGCT?
TCGA
What RNA bases are complimentary to DNA bases: AGCT
UCGA
What does the codon AUG code for?
2 things: “Start” and the amino acid, Methionine
How is a phenotype different than a genotype?
Phenotypes describe the physical expression of the genotype, which is the gene pair for a trait.
Describe meiosis.
Produces haploid gametes
Goes through 2 divisions
Halves the # of chromosomes in cells
When are replicated chromosomes visible?
Prophase and metaphase
What’s the difference between Homozygous and Heterozygous?
Homozygous: BB or bb
Heterozygous: Bb
What is a sex linked gene?
A gene found on a sex chromosome, usually the X.
What are homologous chromosomes?
Matching chromosomes in that they are the same size/shape but also carry genes for the same traits. You would inherit 1 from each parent.
How is cytokinesis in animal cells different than in plant cells?
Animal cells form an invagination called a cleavage furrow while plants form a cell plate.
Which bases are purines?
Adenine and Guanine
Which bases are pyrimidines?
Cytosine, Thymine, and Uracil
How do DNA and RNA differ?
DNA: double helix, 2 sided, Thymine, Deoxyribose.
RNA: single sided, Uracil, Ribose
What are somatic cells?
Diploid body cells
What are gametes?
Haploid sex cells like sperm cells
Contrast co-dominance with incomplete dominance.
Co-dominance: Both alleles are expressed
Incomplete Dom: There is a blending effect with an intermediate form of each phenotype
Who discovered the shape of DNA?
James Watson and Frances Crick, with the help of Rosalind Franklin and Maurice Wilkins
What is a kinetochore?
Protein found near the centromere where spindle fibers attach.
What kind of sex chromosomes are found in male & female gametes?
Females: 1 X only
Males: 1 X or 1 Y
Where do transcription and translation occur?
Transcription: nucleus
Translation: cytoplasm
What are the 4 phase of mitosis in order?
P, M, A, T
How does cell division occur?
First the nucleus is divided (mitosis) then the rest of the cell splits (cytokinesis).
What kind of bonds are found in DNA?
Strong covalent bonds down each side and weak hydrogen bonds across the molecule.
What are carcinogens?
Agents such as U.V. that can mutate DNA.
What is meant by a polygenic trait?
The trait is controlled my multiple genes, not just alleles.
T or F: asexual reproduction produces a lot of diversity.
False: offspring would be clones of the parent organism
What are the 3 parts of a nucleotide?
phosphate, sugar, nitrogen base
What is a mutation?
Any change to the sequence of DNA
What is a gene?
A section of DNA that codes for a protein.
What is the ultimate source of variation?
Mutations
How many genes are involved in epistasis?
More than 1, because one will have the capacity to allow or deny the expression of another gene. Ex: fur color in labs
What is pleiotropy?
One gene causes a phenotype that has a cascade effect on other phenotypes. Ex: sickle cell gene
What is a centriole?
An organelle involved in dividing chromosomes.
What is a centromere?
The spot where sister chromatids attach.
What is an anticodon?
3 nucleotides of tRNA that is complimentary to the codon in mRNA
What is a tetrad?
A tetrad forms when homologous chromosomes attach together during prophase of meiosis.
What happens during cross-over?
Tetrads swap genes to create diversity.
Does dominant mean most common?
No - it means that the dominant gene can mask the presence of the recessive gene. It may or may not be the most common in a gene pool.
Be able to interpret genetic crosses using Punnett Squares.
OK!
Be able to identify various stages of the cell cycle from a diagram.
OK!
