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Gene expression is often controlled by regulatory proteins binding to specific DNA
Some stimulate transcription, while others inhibite
- Control of transcription initiation
- Positive control- increases frequency
- Activators enhance binding of RNA polymerase to Promoter in DNA
- Negtive Control- decreases frequency
- Repressors bind to operatiors in DNA.
Prokaryotic cells often respond to their enviornment by chnanges in gene expression
Genes involved in the same metabolic pathway are organized in operons
CODING REGION contains genes for the use of lactose as an energy source
REGULATORY REGION contains DNA sequences used to control transcription of coding region.
- The lac operon is negatively regulated by a represor protein
- - lac repressor binds to the operator to block trascription,
- - In the presence of lactose, an inducer (allolactose0 binds to repressor
- - Repressor can no longer bind to opperator
- - Transcripton proceeds as BASAL LEVEL.
- Glucose is preferred sugar
- - Catabolic activator protein (CAP) is an activator with cAMP as EFFECTOR
- - Level of cAMP in cells is reduced in the presence of glucose, which prevents CAP from binding to DNA
INDUCER EXCLUSION: presence of glucose inhibits the transport of lactose into the cell.
Genes for the biosynthesis of trypthon
The operon is not expressed when the cell contains sufficient amounts of tryptophan
The operon is expressed when levels of tryptophan are low
- The trp is negatively regulated
- - trp repressor bind to the opperator to block transcription
-Binding of the repressor to the operator requires a COREPRESSOR which is tryptophan
Low levels of tryptophan prevent the repressor from binding to the operator
- Control of transcription more complex
- - Eukaryotes have DNA organized into chromatin (protein-DNA)
Amount of DNA involved in regulation eukaryotic genes is much larger.
- General transcription factors
- - Bind to TATA box on promoter
- -Necessary for RNA polymerase to bind to promoter
- Specific transcription facors (activators)
- -Bind to enhancer sites on DNA
- -Increase the level of transcription
Eukaryotic chromatin structure
Structure is directly related to the control of gene expression
DNA wound around histone proteins to form nucleosomes
Nucleosomes may block access to promoter
- Histones can be modified
- - Correlated with active versus inactive regions of chromatin
- - Can be METHYLATED- found in inactive regions
- - Can be ACETYLATED- found in active regiond
- CHROMATIN- REMODELING COMPLEXES
- - Modify histones and DNA
- - Also change chromatin structure
- Posttranscriptional control of gene expression
- - Small RNAs- miRNA and siRNA
- RNA editing
Micro RNA (miRNA)
miRNA gene transcribed in the nucleus
- Groomed in nucleus and again in cytoplasm
- - Ends with a ~22 nucleotide miRNA
- miRNA loaded into RISC
- - RISC uses miRNA to bind to complementary sequence on mRNA- Cleaves mRNA- inhibits translation
siRNA arise from long dsRNA
Dicer cuts yield multiple siRNAs to load into RISC
Target mRNA is cleaved
miRNA or siRNA?
Biogenesis of both miRNA and siRNA involves cleavage by Dicer and incorporation into RISC
- Main difference is target
- - miRNA repress genes different from their origin
- - siRNAs tend to repress genes they are derived from
Introns are spliced out of pre-mRNAs to produce the mature mRNA
Detemined by tissie- specific factors that regulate how pre-mRNA is spliced
- Initiation of translation can be controlled
- - Ferritin mRNA only translated if iron is present
Mature mRNA molecules have carious half lives
Translation can be controlled by regulating any number of proteins that are required
Creates mRNA not truely encoded by genes
Involves chemical modification of bases
- Apolipoprotein B exists in 2 forms
- - One is produced by editing yhe mRNA to create a stop codon
Phosphorylation or other chemicl modifications alter protein activity
Protein degradation removes damaged or unwamted proteins
Protein produced and degraded continually
Lysosomes for nonspecific protein digestion
- UBIQUITIN for specific destruction
- - Degradation of proteins marked with ubiquition occurs at the PROTEASOME
Weight and length
Double birth weight between 5 and 6 months
Much weight gain is baby fat
Birth length is about 1/4 of ultimate adult height
Head physical growth
Disproportionally large- may be a fourth to a third of body length of the baby
Arms and kegs disproportionately short until about age 6 or 7
Made up of two parts:
Ends are Called Epiphysis-
one on each end of long bone
- Center or Shaft of long bone is called Diaphysis.
- In between epiphysis and diaphysis is cartilage line or "growth line".
Moral Development, Piagetian Approach, Pre-moral Period (0- 7 years)
Evaluates the right or the wrong of the situation by the consequences rather than intention.
Moral Development, Piagetian Approach, Moral Reciprocity (8-11 years)
Moral relationship based on mutual respect
"Ill be nice to you if you are nice to me."
Moal Development, Piagetian approach, Moral Relativity,
(12 years- older)
Realistic application- take all factors into consideration befor you judge.
Moral Development, Kohlberg's Approach, Pre-Conventional Morality (0-9 years)
Child decides what is right or wrong on the basis of what will be punished.
Moral Development, Kohlbergs Approach, Conventional Morality
Live up to what is expected of you.
Good boy or girl
Moral Development, Kohlbergs Approach, Post Conventional Morality (Over 20 years )
Principled morality- achieve the greatest good for the greatest number.
Rules should be based on mutual agreement, not blind authority.
Moral Development,Gilligans Approach boy
Boys think girls feel
Gilligans Stages of moral development, 1. Survival Orientation
Lack awareness of others needs
Gilligan's Stages of Moral Development, 2. Conventional Care
"Right" is whatever pleases others best.
Gilligans Stages of Moral Development, 3. Integrated Care
Right action takes account of self as well as others
Learning Theory, Stimulus Response Reinforcement
Baby sees what he wants, makes a sound to indicate what he sees. Cargiver responds by producing the ball. Next time baby wants a ball, he will say ba. rewarded behavior will be repeated
Learning Theory, Social Learning Theory Bandura
Learning by listening- observing and imitating
Nativist or Psycholinguistic Theory, Noam Chomsky
This is a biologically based theory. Chomsky believed that children have an inborn capacity to learn. The innate capacitiy is called LAD ( Language Acquisition Device) road map to appropriate words.
Interactionist Theory- Piaget
Bothe the linguistic enviornment and the inate biological structure combines to help the child learn language
They must learn sounds of the lanuage
learning the language words
Learning the mening of words
Must learn to be able to piece together thae organization of words into sentences and connected thoughts.
Stage 1 dialation and effacement
Dialation and Effacement
Dilation - widening of the cervix to allow fetus to come out
Effacement- flattening or thinning out of the cervix
Stage 2- delivery of the infant
Presentation: Head- 95%
Double shoulders- Footing-1%
Stage 3 Delivery of placenta
Examined and sent to lab for further examination
Lemaze Method of parenting parents
Labor and delivery should be a natural process
wrote book Birth without trama
cross blood contamination between placenta from mother and baby, treat with Rho Gam
Newborn Assessment APGAR(1953)
Color 2 points for each 10 good to 0 bad
brazelton Neonatal behavior assessment Scale (BNBAS
the most inconvience that is Having in most