Study-Term 2 Flashcards
Genetics
Studies heredity
Heredity is the passing of traits from parents to offspring this involves 2 nucleic acids, DNA and RNA
The big picture
A living organisms is made up of cells which contain in the nucleus chromosomes with contain genes which are made up of DNA
Genes
Genes are a region of DNA made of nucleotides which contain the information to produce a protein or functional RNA molecule
DNA
a nucleic acid located in the nucleus of the cell, double stranded, it’s role is to store coded instructions about how to make proteins, directs cell division, growth and function, the main part of chromosomes
RNA
nucleic acid, located in the nucleus of the cell, single stranded, it’s role is to copy the DNA and create proteins from the DNA’s instructions
DNA structure
Nucleotides are the building blocks of DNA and RNA
nucleotides consist of a five carbon sugar a phosphate group, and a nitrogen containing base, double stranded helix
Components of DNA
DNA and RNA are made up of three parts:
- Sugar- makes up part of the backbone
- Phosphate groups- forms the other part of the backbone
- Nitrogenous bases- bond nucleic acids together (Adenine, guanine, thymine/uracil and cytosine)
Nucleotide
A sugar, phosphate and base
DNA is made up of a series of nucleotides
Nitrogenous bases
there are four bases in a strand of DNA Adenine Thymine Guanine Cytosine
How do the nitrogenous bases pair up
Adenine + thymine
Guanine + cytosine
What is held together by hydrogen bonds
The 2 sides of the ladder
DNA structure (just like a ladder)
The rails of the ladder are represented by the alternating deoxyribose and phosphate
The pairs of bases ( cytosine-guanine or thymine-adenine) form the steps
The process of replication
DNA has the unique ability to make an exact copy of itself
Why does DNA need to replicate before cells divide?
So that the 2 daughter cells have identical copies of DNA
Helicase
Breaks Hydrogen bonds (unwinds and unzips the 2 strands)
DNA polymerase
Adds complementary nitrogenous bases
RNA primase
Adds a primer to each nitrogenous bases
Ligase
Fills gaps in lagging strands and glues the strands together
Lagging
Built in fragments called Okazaki fragments 3’ to 5’
Leading
Built continuously in 5’ to 3’
Karyotype
a ‘map’ of what chromosomes are contained in the nucleus of a particular organisms cells
Body cells
46 chromosomes
Types of chromosomes
The sex chromosomes determine whether you are a boy (xy) or a girl (xx)
The other chromosomes are called autosomes
6 stages of mitosis
Interphase Prophase Metaphase Anaphase Telophase
Interphase
The normal state of the cell (the resting state)
The cell is coping it’s DNA preparing for division
Prophase
Pro=before
The cell is preparing to divide
Chromosomes become visible and pair up
Spindle divers emerge from centrosomes
Metaphase
M=middle
Centrosomes move to opposite poles of the cell
Mitotic spindle is fully developed
Chromosomes have lined up
Spindle divers are attached to each sister chromatid
Anaphase
A=away
Chromatids seperate and are pulled toward opposite poles
Spindle finer lengthen making the cell longer
Telophase
T=two
Chromosomes arrive at opposite poles
Nuclear envelope forms around each set of chromosomes
Mitotic spindle breaks down
Genome
An organisms complete set of DNA including all of its genes. Each genome contains all of the information needed to build and maintain that organism. Protein synthesis is the process in which cells make proteins. It occurs in two stages: transcription and translation
Transcription
Transcribes the DNA into a message (MRNA), occurs in the nucleus, initiated by RNA polymerase, Delivers MRNA out of the nucleus into the cytoplasm to find a ribosome(protein factory) to begin translation. RNA uses the base ‘uracil’ instead of thymine
Translation
The process of creating proteins from an MRNA template. The sequence of nucleotides on the RNA is translated into the amino acid sequence of proteins and this reaction is carried out by ribosomes
Translation
MRNA bases—>3 bases=codon—>amino acid—>protein
Codon
Made up of a series of three bases each bases carry a code for a particular amino acid when a chain of amino acids are put together this creates a protein
In transcription
a DNA sequence is rewritten or transcribed into a strand of MRNA it is intimated by RNA polymerase and occurs within the nucleus of a cell to be delivered out into the cytoplasm to a ribosome
In translation
The sequence of the MRNA is decided in the rRNA by the tRNA to create the. Amino acid sequence of a polypeptide (protein chain)