Unit 2: Lecture 1 Flashcards
What is a genome?
all of the genetic material, USUALLY DNA, transmitted from parent to offspring
What does a haploid human genome contain?
23 chromosomes
What is a diploid human genome?
maternal copy and paternal copy of chromosomes, plus mitochondrial DNA
Is the genome entirely contained in the nucleus?
no
Compare chromosomal structure in bacterial vs. eukaryotic cells.
chromosome
cell
DNA
bacterial
chromosome: circular
cell: haploid
DNA: double-stranded
eukaryotic
chromosome: linear
cell: diploid
DNA: double-stranded
What is a haploid cell?
contains one set of chromosomes
What is a diploid cell?
contains two sets of chromosomes (one maternal, one paternal)
How is DNA packaged in bacterial cells?
all DNA in the cell is tightly wound (supercoiled)
What is genome size?
number of base pairs
genome size is small, then cells are small
What is a bacterial nucleoid?
the bacterial chromosome twists on itself to form supercoils, which are anchored by proteins
How is DNA packaged in eukaryotes?
DNA is wound around proteins called histones and wound into chromatin
when cells divide in mitosis or meiosis, the chromatin is further wound into the chromosome
What does each chromatid have?
one long piece of DNA double helix wrapped up
each chromosome has two chromatids before the cell divides
- 23 pairs of homologous chromosomes (one chromosome in pair from mother, one from father)
- 46 chromosomes with two chromatids prior to mitosis
- 92 double DNA helices
- if you heated the DNA to separate the strands of the double helix, there would be total 184 DNA individual strands
What is one eukaryotic chromatid equal to?
one linear DNA double helix
What is one eukaryotic chromosome equal to?
two chromatids
What is a phenotype?
observable characteristics and traits
What is a genotype?
genetic make-up of a cell or organism, the sequence of the DNA
What is a gene?
unit of hereditary information consisting of a DNA sequence
What is the sequence of genes?
a sequence of bases in a region of the DNA that can code for a protein (via mRNA) or RNA (tRNA or rRNA)
Describe the relationship between genotype and phenotype.
genotype is DNA sequence in on or more genes that encode proteins whose function determines traits
What are the bonds or interactions between bases?
hydrogen bonds
What is the backbone of DNA made of?
two strands: one phosphate and one sugar
What type of interactions are hydrogen bonds?
intermolecular
What tends to have similar genomes?
prokaryotes
