Lect 2 - Chromosomes, DNA replication, Cell cycle

Question 1

Explain how a large amount of genetic material is able to fit in such a small space

Answer 1

DNA - histones - chromatin - chromatids

Question 2

Describe the process of DNA replication, include the functions of relavent enzymes

Answer 2

DNA replication occurs during mitosis and meiosis.
DNA is opened by helicase at A=T joint, RNA primase then lays down starter of RNA nucleotides, from here, DNA pol III moves in 5’ to 3’ direction adding on complementary base pairs.
DNA pol I will then remove RNA starter sections, and DNA ligase will insert phosphate into gaps to “glue” the chains together.

Question 3

when does DNA replication occur during cell division?

Answer 3

interphase

Question 4

what are the two types of packing for chomatin

Answer 4

heterochromatin - AT rich, tightly packed

euchromatin - CG rich, loosely packed (more coding)

Question 5

what gene expression

Answer 5

process by which information from a gene is used in the synthesis of a functional gene product.

whereas DNA is fairly rigid, RNA and proteins are in state of constant flux, and gene expression influences things from cell development, cell differentiation.

errors in DNA replication can lead alter normal gene expression, leading to a change in natural biology of organism