Biology investigation

remember to learn diagrams!!

What did Rosali discover and what did that lead to

she applied X-ray diffraction methods to study the structure of the DNA, leading her to discover the density of DNA and the helical makeup of the molecule with an image she captured called ‘Photo 5.’

plus+ as James Watson and Francis Crick in 1953 to propose that the structure of DNA is a double-helix

Locations of dna in the cell

Located in the nucleus of the cell, surrounded by the nuclear membrane, 

Structure and function of dna

a.                  The structure of DNA involves a series of two phosphate sugar backbones, connected together by complementary nitrogenous bases by hydrogen bonds. 

a.                  DNA helps determine how cells can determine their appearance, serving as the ‘blueprint’ of the cell.

They also dictate the functions of the cells by sending messages to the ribosomes in the rough endoplasmic reticulum or cytoplasm. In the ribosomes, the synthesis of proteins takes place. The production of proteins are vital since they serve many functions significant to the development of the organism.

Base pair rule

The four kinds of base pairs, adenine, thymine, cytosine, and guanine have specific pairings that they need to go by. Adenine (A) goes with Thymine (T), and Cytosine (C) goes with Guanine (G). 

Chromosome

Chromosomes consist of two chromatids that are connected by their centromeres. They are long strands of DNA which are wrapped around the protein histones, therefore compacting them into a size suitable to fit inside the nucleus. 

Gene

A certain section of a DNA strand. Some genes serve as a formula for a specific protein. Some genes do otherwise, and not code for any protein at all. 

e.g ) a gene can produce a protein that changes the colour of someone's hair, skin, etc. 

Importance of meiosis

Meiosis is an important process for reproduction. It prevents the offspring from being identical to each other and the parents, so they have different genes, leading to different capabilities for survival. For example, on dirt, brown mice can easily camouflage themselves, but white mice cannot, so they are prone to predators and are most likely to exinct.  

Outline the eight major stages of meiosis

 Prophase 1: Crossing over (they transfer genetic information)

Metaphase 1: The chromosomes will line up in the middle of the cell in pairs

Anaphase 1: chromosomes are pulled away by spindle fibres that are attached to the centromeres

Telophase: Two daughter cells

Prophase II - The chromosomes coil up, and the centrosomes begin moving apart

Metaphase II - chromatids line up in the middle in a single file line

Anaphase II - chromatids pulled away by spindle fibres

Telophase II - nuclei forming, 4 cells

nucleotides and its components

A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T).

Codon

A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid

Anticodon

Each tRNA contains a set of three nucleotides called an anticodon