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Biology genetics

Terms in this set (50)

DNA replication
helicase unzips DNA into two parts and splits with the cell. Then DNA polymerase attaches complementary bases to the original strand in the 5' to 3' direction and proof reads the strand. Primase makes short RNA primers to help get the polymerase started and DNA ligase seals the gap in DNA.
pyrimidine
T, C, U
smaller bases
DNA
One long molecule containing the genetic information
Chromosomes
tightly coiled strands of DNA
genes
specific piece of DNA with code for one protein.
DNA vs. RNA
DNA: deoxyribose sugar, thymine, double strand
RNA: ribose sugar, uracil, single strand
Purines
A, G, and a larger base
Structure of DNA molecule
Double stranded helix, runs anti parallel- first strand is 5' to 3', second is 3' to 5'. sugar and phosphate make up backbone of DNA molecule and bond with strong covalent bonds, while nucleotides bond with weak hydrogen bonds.
Structure of a nucleotide
phosphate group, sugar, nitrogenous base
Base pairing rules for DNA
A-T
G-C
Leading Strand vs. Lagging Strand
works toward replication fork / works away from replication fork; both always move in the 5' ➝ 3' direction, the leading strand only uses one RNA primer, while lagging uses many. The leading strand is also made continuously while the lagging strand is made discontinuously.
nucleic acids
a macromolecule that carries our genetic material (DNA)
DNA
deoxyribonucleic acid that carries genetic information
Okazaki fragments
short pieces of DNA created by lagging strand
Semi-conservative model
two new strands formed with one original strand and one new strand
relationship between genes and proteins
The genetic code in genes is read to make proteins.
the central dogma
DNA(instructions) is in the nucleus but proteins are made in the ribosomes so protein synthesis takes two steps, transcription and translation.
mRNA
(messenger): copies instructions in DNA and carries to the ribosomes.
tRNA
(transfer): carries amino acids to the ribosome and mRNA.
rRNA
(ribosomal): composes the ribosome.
Steps in Transcription
occurs in the Nucleus. First RNA polymerase binds to the DNA and unzips the gene that needs to be copied. RNA polymerase uses complementary base pairing rules match RNA nucleotides with exposed DNA nucleotides. The completed mRNA molecule is released from the nucleus and leaves the cytoplasm and the DNA zips back up.
Steps in Translation
occurs in the cytoplasm/ ribosomes. First the mRNA attaches the small subunit of the ribosome. The ribosome reads the mRNA codons always in the 5' to 3' direction, starting at codon AUG. tRNA molecules pick up and drop off the amino acids tat match with the current codon being read off the mRNA. tRNAs continue to drop off amino acids, and the ribosome binds the amino acids together with peptide bonds. Finally, when the stop codon is reached, the ribosome releases the completed protein.
if a mistake is made during protein synthesis
proteins wont be made, therefore the body will lack enzymes and not function properly.
Transcription
DNA is copied into a complementary strand of mRNA
Translation
interpreting the RNA message into a protein
Genetic code
code of instructions for how to make proteins
Codon
a set of 3 nucleotides on the mRNA
Anticodon
"complementary" 3 nucleotides on tRNA
Amino acid
monomer for making proteins, held together by peptide bonds
haploid vs diploid cells
Haploid - Contain only one set of chromosomes
Diploid - Contains two sets of chromosomes; one from each parent
significance of crossing over during prophase 1/ metaphase 1
creates DNA that are combinations of mom and dads genes.
somatic cells
Body cells(diploid 2n)
gametes
sex cells(haploid n) like egg and sperm
autosomes
carries defining traits in first 44 chromosomes
sex chromosomes
carry genes that determine sex, chromosomes 45- 46(X or Y)
Meiosis vs. Mitosis
- meiosis has 2 cell divisions, mitosis only one
- in meiosis homologous chromosomes pair up on cell's equator, in mitosis homologous chromosomes never pair up
- in anaphase 1 of meiosis sister chromatids are still paired, in anaphase in mitosis, sister chromatids are separated
- meiosis results in a haploid cell, mitosis results in a diploid
- meiosis has two cell divisions, mitosis only one
end result of Meiosis 1
2 haploid daughter cells that are different from original diploid cell
end result of meiosis 2
4 genetically unique haploid daughter cells
prophase 1
Chromosomes become visible; nuclear envelope breaks down; crossing-over occurs.
Interphase(meiosis)
chromosomes in a cell are duplicated
Metaphase 1
Paired homologous chromosomes line up across the center of the cell
Anaphase 1
homologous chromosomes separate and are pulled to opposite ends of the cell
telophase 1 and cytokinesis (meiosis)
nuclear membrane forms again and spindle fibers disassemble then the cell undergoes cytokinesis
Prophase 2 (meiosis)
A new spindle forms around the chromosomes
metaphase 2 (meiosis)
sister chromatids line up along the center of the cell
Anaphase 2 (Meiosis)
sister chromatids separate and move to opposite poles
telophase 2 (meiosis)
A nuclear membrane forms around the chromosomes in each of the 4 new cells.
Karyotype
A display of the chromosome pairs of a cell arranged by size and shape.
crossing over
exchange of genetic material between homologous chromosomes during prophase I of meiosis
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