Class Notes (808,171)
Canada (493,054)
Psychology (7,612)
PSYB32H3 (614)

PSYB20 Ch 2.docx

6 Pages
Unlock Document

University of Toronto Scarborough
Mark Schmuckler

PSYB20 - Each reproductive cell only contains 23 SINGLE Chapter 2 Heredity and the Environment chromosomes instead of 46 single ones o This is because during development, the The diversity of newborns: reproductive cell undergoes a special - From the moment they are born, babies differ form of cell division called meiosis from one another in: Physical appearance & o So the when the egg and sperm unite, behaviour 23 + 23 can combine to give 46!! What contributes to these individual differences at such How is the tremendous diversity of genetic a young age? combinations facilitated in organisms? - Transactions between hereditary and - Crossing over: equivalent sections of homologous chromosomes randomly switch environmental factors begin before birth - Such transactions between genes and the places to shuffle genetic info environment make each newborn unique - Halving of the chromosomes during meiosis mixes the chromosomes that originated from The interaction of genes and environment: the mother with the chromosomes that originated from the father - Genotype: the particular set of genes that a person inherits from her parents - Phenotypes: the visible expression of the How does the single zygote become a complex human persons particular physical and behavioural being? characteristics - By a process called mitosis: the cell duplicates its chromosomes and then divides into daughter - Phenotypes are created by the interaction of a persons genotype, with the environment cells that have the same # of chromosomes What do psychologists study? Genes, DNA, and Proteins - Phenotypes What is the chromosome? - A thin molecule of deoxyribonucleic acid, DNA - Ex. motor abilities, intellectual skills, social behaviour, and personality traits o A ladder like molecule that stores gentic information in cells and transmits it THE PROCESS OF GENETIC TRANSMISSION during reproduction - The female egg: (ovum) o Its made up of nucleotides o Each nucleotide: is a compound o The largest human cell o 90 000X heavier then sperm consistent of a nitrogen-containing base, a simple sugar, and a phosphate o Has genetic info (23 chromosomes) - The male sperm: group (A-T or C-G) o Smallest of all human cells How do chromosomes carry the units of hereditary o A head with a whip-like tail o Has genetic info (23 chromosomes) information? - Portions of the chromosomes called genes, are - Each chromosome is homologous: the shame and functions of 23 females are = to 23 males located a particular sites on the chromosome, - In the womens oviduct Female egg and male and code the production of certain kinds of proteins sperm unite to create: zygote which has 23 chromosome pairs OR 46 chromosomes - Specific bases put in a certain order code for a protein - Copies of these 23 PAIRS of chromosomes are passed on to every cells in a persons body - Proteins serve multiple functions in the - EXCEPT: the reproductive cells organism: structures, chemical triggers...GENETIC INFLUENCES ON DEVELOPMENT Genetic Disorders The transmission of Traits: A Basic Model Why do Harmful alleles survive? - They are not harmful in the heterozygous state How are characteristics inherited? - Gregor Mendel: observed generations of peas 1. Phenlketonuria (PKU) and worked the the mechanisms, or laws of the - Caused by a recessive allele inheritance of characteristics - Failed production of an enzyme that 1. The principle of segregation: Each inherited trait metabolised a protein in milk comes from ones parent as a separate unit (Ex. - Person heterozygous with this allele is OK flower colour, stem height) - Untreated homozygous infants have 2. The principle of independent assortment: the accumulation of toxic substances, damaging the inheritance of various traits occurs NS and causing mental retardation independently of one another (Ex. inheritance 2. Chromosomal abnormalities of colour has nothing to do with height) - ENTIRE defected chromosome - Created during the process of meiosis There are two concepts crucial to understanding genetic - These zygotes usually abort influences on development: 3. Sickle-Cell anemia - Genes typically have two forms: alleles, one - Normal red blood cells become elongated and from the mother and one from the father bent into the shape of a sickle - If the alleles from the two parents are the same, - They may get stuck in vessels, or removed by the individual is homozygous, if the alleles are spleen causing chromic anemia (low blood cells) different, the organism is heterozygous - Recessive alleles on chromosome 11 - POSITIVE EFFECT OF THIS ALLELE: ability to fight The combinations of alleles from both parents can have of
More Less

Related notes for PSYB32H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.