intro to biopsych Flashcards
what is the plasma membrane
The boundary between the cell and it’s environment
Maintains Homeostasis
GO: good stuff, nutrients STOP: bad stuff, waste
Selective permeability Allows some molecules into the cell and keeps some out § Some molecules can cross the plasma membrane (water) § Others must go through channels (Sodium (Na), Calcium (Ca))
what is the nucleus?
The leader of the cell
Gives directions for the making of proteins The master set of directions is in chromatin During cell division, chromatin condenses to form chromosomes
§ Inside the nucleus is the nucleolus Makes ribosomes § Ribosomes are sites where proteins are made, according to instructions from DNA
outline how proteins are synthesissed
Proteins are synthesized from a “menu” of 20 amino acids
The amino acids must be put together in the correct sequence
The amino acid sequences of thousands of proteins have evolved over billions of years
In order for proteins to be synthesized, the cell must “know” the correct sequence §
Life is dependent upon each cell having a complete set of instructions for the amino acid sequence of every protein in the cell
Consider the amino acids as the 20 “letters” of the protein “alphabets”:
Each protein forms a word –the number of possible words is infinite!
outline amino acids
Small molecules based around a carbon chain with an amino group and a carboxyl group- 20 amino acids
Building blocks of proteins
Outline what DNA is
DNA is the blueprint of all living organisms
DNA controls the organisms through the production of proteins
Proteins, many in form of enzymes, are responsible for all functions of life
Deoxyribonucleic acid-The DNA of each gene carries the chemical code that tells the cell the correct sequence of amino acids required to produce the protein that that gene codes.
The code is contained in the sequence of ”bases” of 4 nucleotides: Adenine and thymine pair together like a lock and key Guanine and cytosine pair together due to their complementary shapes
The precise sequence of triplets of bases provides the code for each amino acid in the protein the gene codes for DNA
give the three types of RNA and how it differs from DNA
In order to make the proteins we need RNA
RNA is also a nucleic acid (like DNA)
There are 3 ways in which RNA differs from DNA:
- RNA is single stranded
- The sugar in RNA is Ribose instead of deoxyribose
- RNA has uracil instead of thymine
Messenger RNA (mRNA); codes for proteins: carries the genetic information copied from DNA in the form of a series of three-base code “words” à amino acid
Ribosomal RNA (rRNA): Forms part of the ribosome: associates with a set of proteins to form ribosomes –a machine involved in translation of RNA into protein
Transfer RNA (tRNA) transports the amino acid to the ribosome: Binds amino acids and bring them to the ribosome during protein translation deciphering the code in mRNA
how is DNA transcribed to proteins
The genes in DNA encode protein molecules, which are the “workhorses” of the cell, carrying out all the functions necessary for life
Expressing a gene means manufacturing its corresponding protein
the information in DNA is transferred to a mRNA molecule by way of a process called transcription DNA of a gene serves as a template for complementary base-pairing, and an enzyme called RNA polymerase-
mRNA is “read” according to the genetic code, which relates the DNA sequence to the amino acid sequence in proteins
Translation- Involves ribosomes using the mRNA as a blueprint to synthesize a protein composed of amino acids
what is a chromesome?
a package containing a chunk of a genome -it contains some of an organism’s genes.
Chromosomes help a cell to keep a large amount of genetic information neat, organized, and compact.
Exactly how many chromosomes w are talking about depends on the species
How many chromosomes do organisms have? 23 pairs –46 usually in total
Is DNA relevent for psych?
Rett Syndrome A genetic disorder that causes mental retardation and impairs movement- very severe- in a few years may not be able to move or talk
MECP2 gene The gene lies on the X chromosome – females with a faulty copy usually have a normal version too, males with a mutated MECP2 gene do not usually survive beyond infancy
Guy et al (2007) disabled the MECP2 gene in mice by placing an irrelevant sequence of DNA in the middle of the gene
The animals developed the symptoms of Rett syndrome between 4 to 12 months after birth
Mecp2lox-Stop – 12 weeks
Guy et al gave them a drug that triggered an enzyme to cut out the irrelevant sequence within the MECP2 gene
4 weeks
MECP2 gene- therefore a treatment may be possible I f you can cut out the non-functioning gene
