DNA Structure Flashcards
What are the 3 parts of DNA?
Nucleotide, Phosphate backbone and deoxyribose sugar
What is the shape/formation of a DNA strand?
Double helix
What are the complementary base pairs?
Adenine - Thymine
Guanine - Cytosine
What is the role of NDA helicase?
Unwinding of the double helix and separation of the strands during Transcription and DNA replication
What is the role of DNA Polymerase
Matches complementary base pairs in DNA with complementary pairs of mRNA.
What is the direction of replication during DNA replication?
5’ –> 3’
What is the difference in nucleotide bases between RNA and DNA?
Thymine - Uracil
What are the 3 types of RNA and what are their roles?
mRNA - carries a copy of the DNA’s nucleotide sequence to be translated into proteins
rRNA - form ribosomes, the site of translation of the mRNA into proteins
tRNA - carries amino acids to the appropriate positions on the mRNA by matching its anticodon sequence to the complementary sequence in the mRNA
What are histones?
Histones are proteins that DNA wrap around providing the DNA with structure and stability.
What is the role of homologous chromosomes?
Homologous chromosomes pair up during meiosis, allowing for exchange of genetic material through crossing over. This paring and exchange occurs during prophase l.
Describe the process of crossing over and recombination and demonstrate how they contribute to genetic variation
During meiosis, crossing over occurs during prophase I when homologous chromosomes pair up. At specific points called chiasmata, segments of these chromosomes break and exchange genetic material. This recombination results in new combinations of genes on the chromosomes, increasing genetic variation by creating unique DNA sequences in the resulting gametes, ultimately contributing to the diversity observed in offspring.
What are the similarities and differences between spermatogenesis and oogenesis?
Spermatogenesis and oogenesis are both processes of gamete formation but occur in different sexes. Both processes involve meiotic divisions to produce gametes, but spermatogenesis in males generates four functional sperm cells, while oogenesis in females yields one mature egg cell and polar bodies through meiosis, resulting in uneven distribution of cytoplasm. Additionally, spermatogenesis begins at puberty and continues throughout a male’s life, while oogenesis begins before birth and progresses to a certain stage, pausing until puberty and continuing in cycles until menopause.
