Chapter 11 Flashcards
Gene Expression means that ___
not all genes are turned on all the time
Gene regulation is the ability of a gene to ______________________
turn on/off a specific phenotype
what is differentation in gene expression
allows the embryonic stem cells to become different specialized cells
How would gene expression change as an individual ages from infacy into adulthood
it changes to send energy where is needed
EX: Hair color changes to grey to remove energy from that cell
Gene expression: DNA -> _____ -> _____ -> Proteins
DNA -> mRNA -> amino acids -> Proteins
identify the benefit of E coli only making enzymes to use lactose when lactose is present and glucose is absent
it allows it to only use that energy when both factors are present, creating efficent energy use
Humans begin as ______ and ______ which form a _______
egg/sperm which form a zygote
What types of genes must be expressed in the phenotype of nervous system cells
Neurotransmitter-related genes
What types of genes must be expressed in the phenotype of Skin cells
sensory receptor genes
What types of genes must be expressed in the phenotype of White Blood Cells
antigen receptor genes
What types of genes must be expressed in the phenotype of Muscles
contractile protein genes
What types of genes must be expressed in the phenotype of Red blood cells
hemoglobin genes
the tighter packed the genes are the ______ expression is
harder
Define metylation in Gene expression
occurs when a methyl group, -CH3, attachs to the cytosine on DNA, keeping the gene condensed and not expressed
Can methylated DNA be passed down? What is this called?
Yes
Epigenetic inheritance
Define Epigenetic inheritance
not invloving nucleotide sequence
passed through Daugther cells what genes are methylated or not
In Women: ______ in Embryotic development one of the two X chromosomes in each cell becomes inactive by condensing tightly into a _______
Early
Barr Body
Why is X inactivation important
to balance representation of genes
How does X inactivation contribute to coat color in animals like tortoiseshell cats
Which X is inactivated is random so it creates patches with different inactivations
what are homeotic genes
genes that are “Master control genees” control many other genes and help determine which end of a zygote is head of tail and the position of major body parts
What happens if homeotic genes are mutated
mmutted anatomy that can result in death
Reproductive cloning is achieved through ___________
nuclear transplantation
Steps of reproductive cloning
1.) nucleus of an egg is replaced with nucleus of adult somatic ell
2.) the nucleus divides
3.) BLASTOCYST is formed: hollow ball of ~100 cells
4.) Bastocyst is implanted
List some animals that have been cloned
sheep, dog, cat, pig, fly, human
Clones will be identical to ____________
somatic cell donor
What is therapeutic cloning
creates organs
How are adult stem cells used in therapeutic cloning?
can be used for SOME specialized cells
what does the term pluripotent mean? What type of stem cells are usually pluripotent
Embryotic
all specialized cells are avalible
Oncogenes
Proto-oncogenes
Tumor suppressor:
Tumor:
O: Cancer causing cells
PO: Normal cell w/ potental to be cancerous
TS: Inhibits uncontrolled cell division (P53 gene)
T: Uncontrolled growth
How can a proto-oncogene become a oncogene
Chemical: Drugs/alcohol
Physical: X-ray/UV
Virus/Bacteria
What are the top 5 carcinogenes
Tobacco, smoking, processed meat, pollution, and UV rays
Decribe how carcinogens cause cancer
Continuing exposure to these things causes mutations to happen in your genes, and if you have 4 or more mutations you are going to likely get cancer.
How could lifestyle increase/decrease cancer risk
Smoking greatly increases, age also increases
Healthy diet can decrease
Since all of the cells of the body (execpt gametes) have the same genotype, explain how different cell types can express different phenotypes
Because environmental factors and how someone grows up will alter their phenotypes.
List some benefits of the ability to turn certain genes on and off
Allows response to environmental changes
What is a fertilized egg called? How many chromosomes does a human on have?
Zygote; 46
Explain the concept of differentiation in eukaryotes
Cells become specialized in structure and function
How do all of the trillions of cells in the human body express the correct genes for their function?
Specialized gene expression
Desribe how DNA is packaged into Chromosomes. How does the packaging of DNA affect gene expression?
Histones: PRotein for DNA packagin
Nucleosome: 8 histones + DNA
Linker: Streches of DNA that connect to a nucleosome
if a gene is tightly packed will it express more or less easily?
less
Describe DNA methylation and what hapens to a gene that is methylated
Add methyl group to cytocine to turn gene off
It no longer expresses that gene
Define Epigenetic inheritance
inheritance of traits transmitted by mechanisms not directly invloving nucleotide senquence
Why don’t Females have double the amount of proteins coded for by the X Chromosome?
X Inactivation: one X Chromosome in each somatic cell inactivates in females by condensing into barr body effect
how are barr bodies formed
one X chromosome becomes inactive and condenses tightly
Are most eukaryotic genes turned on or off? Which is more imprtant in gene expression, activators or repressors?
Most genes are turned off. They are both important, because repressors decrease/halt transcription and turn off certain genes in the body, and activators regulate your gene expression by promoting transcription.
What is a homeotic gene and why are they important
Master control genes that determine the anatomy of the body
Important for normal body arrangement
Explain the steps in Eukaryotic cloning
Replace nucleus of an egg cell (receptient) with nucelus of an adult somatic cell (Donor)
Explain why embryotic stem cells are harvested at a particular time in development
Embryotic stem cells give rise to all specialized cells while adult ones only have some
How does reproductive cloning differ from therapeutic cloning?
Theraputic is for repair of damaged/diseased organs
Reproductive makes a whole new organism
What is an adult stem cell? what are they used for and what are their limitations?
Stem cells from adults only have some specialized cells, used for theraputic cloning
Define oncogenes, proto=oncogenes, and tumor-suppressor genes
and their importance
Onco: Cancer causing genes
Proto: normal genes w/ potential to become an oncogene
Tumor Suppressor: Inhibit uncontrolled cell division
Important in the identification and suppression of cancer
What might make a proto-oncogene become an oncogene?
demethylation
How do oncogenes cause cancer? how do tumor supproessor genes counteract oncogenes?
Oncogenes cause cancer because they cause the cell to divide and multiply uncontrollably. Tumor suppresor genes code for proteins that prevent or suppress cancer in an active form. They also code for apoptosis, or cell self deleting.
what is meant by: “Most cancers are caused by more than one mutation”? How does this work? What errors must occur to allow the formation of a tumor
Mitosis error
Gradual accumulation of mutations that cenverts into proto-oncogenes to oncogenes and mutations/loss of tumor-suppressor genes
Describe a carcinogen. Identify the most common carcinogen
Cancer causing agents.
Drugs (Tobacco)
How do life choices counteract carcinogens?
Whatch what you eat and put in your body
Would 2 clones animals look and behave identically? Explain how identical twins might express different proteins
They would look the same but act differently as they have different brains
Epigenetic inheritance
_______ gene help determines where legs and arms will develop.
Homeotic gene
The units of hereditary information are called
Genes
During RNA splicing, _____ are removed from the original mRNA sequence to produce the resulting mRNA.
introns
A repressor is controlled by a ________.
regulatory gene
Due to alternative ________ one gene can result in multiple polypeptides.
RNA splicing
Embryonic stem cells are harvested from the _________.
blastocyst
Prokaryotic ____________ initiates gene transcription without the assistance of transcription factors.
RNA polymerase
T/F The tortoiseshell trait in cats is found on the X chromosome. Due to X chromosome inactivation, tortoiseshell cats are always females.
FALSE
A gene that when present can cause cancer is called an _______-.
oncogene
