Multicellular Organisms
Why is protein synthesis important?
It produces the protein bases required by the organism to function properly, allowing for cell growth and function.
Where does transcription occur?
In the nucleus
What steps are involved in transcription?
1. DNA unwinds to expose the gene
2. RNA polymerase binds to the DNA to form complementary base pairs.
3. RNA polymerase makes the messenger RNA molecule.
Where does Translation (mRNA) occur?
In the cytoplasm
What steps are involved in translation?
1. mRNA is transported out to ribosomes in cytoplasm
2. Ribosomes attach to mRNA to assemble amino acids in codons into a polypeptide.
What is gene expression?
Certain genes are turned on and off during key moments of organisms's growth (EXAMPLE - healthy adult had genes turned on/off during puberty). This means only certain proteins are synthesised. RNA polymerase must bind to the DNA near promoter of a gene.
What is gene expression responsible for?
Cell specialistion.
What are the three fundamental untis of genetic information?
DNA, genes, and chromosomes
What is DNA?
Found in nucleus, contains the information for synthesising proteins. Chemical unit of genetic information.
What are genes?
Functional unit of genetic informaton, formed by specific DNA sequences. Genes determine protein sysnthesis, physical characteristics of organisms and inheritance of each generation.
What are chromosomes?
Structural unit of genetic information. Each chromosomes is a large DNA molecule and are visible when the cell divides.
What is a chromosomes made of?
DNA and proteins --> DNA double helix strand.
What is protein synthesis?
The process where the double helix strand is unwound to expose genes for the production of new poteins.
How do cells switch genese on/off?
Activators (protein) bind to gene's promoter, the DNA shape changes (OPENS) to make the gene accessible to RNA polymerase.
Repressors (protein) bind to gene's promoter, surrounding histone structure changes making DNA tight, preventing accessibility of gene to RNA polymerase.
What are specialised cells?
Cells that have undergone adaption/s through cell differentiation to perform specialised functions.
Cells within a mulitcellular organism are ...
Genetically identical until having undergone gene expression.
What are the complementary base pairings of DNA (double helix strand)?
Adenine and Thymine
Guanine and Cytosine
What are the complementary base pairings of RNA?
Adenine and Uracil
Guanine and Cytosine
Example of plant hieracrchal structure
xylem cell - xylem tissue - stem - shoot system
Animal hierarchial structure example
smooth muscle cell - muscle tissue - oesphagus - digestive system
What are stem cells?
Undifferentiated cells that have the ability to be developed into other cells types. Stem cells can divide and replicate for long periods of time.
What is a tissue?
A group of similar cells that work together to perform a specific task.
What is an organ?
Different types of tissues that work together to enable the organ to carry out a specific function within a system.
What is a system?
Different organs work together to perform important jobs for organism.
What are the four features of an exchange surface?
1. Thin - Minimises distance sunbstances travel
2. Moist - Allows for diffusion of soluable substances.
3. Large Surface Area - Maximise amount of substances that can be exchanged.
4. Large supply of blood capillaries