Chapter 5: DNA & Chromosomes
Prokaryote chromosomes
- Consist of a CIRCULAR DNA molecule - NAKED - no associated proteins - PLASMIDS often present - ONE CHROMOSOME only
5.2.c Recall how many molecules of DNA are in each eukaryotic chromosome.
1 molecule of DNA per chromosome.
Centromere
Area where the chromatids of a chromosome are attached
5.2.h Compare the roles played by centromeres and replication origins.
Centromere: Sequence of DNA- where chromatids are attached. Replication: Sequence of DNA- where DNA replication begins.
5.1.e Describe complementary base-pairing and explain how this arrangement gives rise to the twisting, consistently proportioned, double helical structure of DNA.
Complementary base pairing enables base pairs to be packed in the energetically favorable arrangement along the interior, but need to be in a certain width from each other. In order for this to happen, the two strands need to run antiparallel (be oriented with opposite polarities)
5.1.a Contrast the functions of the DNA and protein components of chromosomes.
DNA carries genetic information, whereas protein components f(x) to package and control the DNA molecules.
Central Dogma
DNA-transcription-RNA-translation-protein
5.1.g Explain how the structure of DNA carries information for producing proteins.
Genes, segment of DNA, contain information for making protein. Central Dogma.
5.2.e Define the terms "gene" and "genome."
Genes: the biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein Genome: the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes
Complementary base pairing
Hydrogen bonding between particular pyrimidines and purines. Adenine & Thymine- Purine. Cytosine & Guanine- Pyrimidines.
What bonds the two strands of DNA together?
Hydrogen bonds: Link the base portions of the nucleotides, thus holding the 2 strands.
Nucleic acid monomer and polymer
Monomer: nucleotide Polymer: DNA/RNA
5' end of DNA
OH or phosphate group on the C5 carbon of the deoxyribose
Sex Chromosomes
One of the 23 pairs of chromosomes in the human, contains genes that will determine the sex of the individual.
What bond nucleotides in a single strand of DNA?
Phosphodiester bonds: link the 5' end of one sugar to the 3' end of another.
Replication Origin
Specific sequence of DNA where DNA synthesis begins.
5.1.f Describe the chemical differences that dictate the polarity of a DNA strand.
The ester linkage to the sugar molecules on either side of the bond are different, each DNA has a chemical polarity. The 3' C Hydroxyl: 5' C Phosphate
5.1.h Explain how the structure of DNA suggests a mechanism by which genetic information can be copied.
The nucleotide sequence in a gene, the segment of DNA, allow for genetic information to be copied.
5.2.d Describe a full complement of human chromosomes in a diploid somatic cell, including sex chromosomes.
linear DNA associated with histone proteins; different chromosomes carry different genes (different in size & location of centromere, 23 types of chromosomes in human cells, each chromosome can carry thousands of genes); homologous chromosomes (carry same gene sequences, but not necessarily same alleles, allows for interbreeding, 1 from mom & 1 from dad)
Eukaryote chromosomes
linear DNA associated with histone proteins; different chromosomes carry different genes.
3' end of DNA
refers to the end that has a hydroxyl group attached to the number 3 carbon of deoxyribose AND attaches to the 5' phosphate group of the incoming nucleotide.
Diploid Somatic Cells
somatic cells, full # of chromosomes, ex: every other cell in the body (46)
Antiparallel DNA
strands of DNA run in opposite directions, sugar-phosphate backgrounds are arranged in opposite directions, one in 5' 3' and the other 3' 5;
Genes
the biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein
Genome
the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes
