Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
75 Cards in this Set
- Front
- Back
Allele
|
Different gene sequences among all humans.
|
|
Polymorphism
|
Differences in DNA sequence. NOT a mutation.
|
|
Mendel's Observations
|
Bred pea plants.
Observation 1: some alleles are dominant over others. Observation 2: Alleles Segregate |
|
How did Mendel Conduct His Experiment?
|
Po = parental plants were True bred... meaning that the offspring produced from self-fertilization remained uniform from one generation to the next.
F1 = He bred purple x white sexually and found all to be purple. F2 = He bred the purple x purple from end of F1 to find 75% P and 25% W |
|
Genotype
|
Describes gene sequence
|
|
Phenotype
|
How gene sequence are interpreted physically.
|
|
How do we get functions from genes?
|
genes -> proteins -> function
unique genome -> unique proteome -> unique phenotype. |
|
Somatic vs Germline Mutation
|
Somatic - not passed on (ie: UV radiation)
Germline - passed on (ie: X ray) and produces gametes (sperm and egg) |
|
Mendel Ratio
|
Found that phenotypes exhibit a 3:1 ratio while genotypes are 1:2:1 (true breeding dominant, not true breeding dominant, true breeding recessive).
|
|
Punnet Squares
|
Predict patterns of inheritance
|
|
Genetic Diseases
|
Sickle Cell Anemia - recessive disease allele (carriers not affected)
Huntington's - dominant disease allele (carriers affected) Hemophilia (recessive, X linked) |
|
Mitosis
|
Division of the cell that results in generation of two, genetically identical daughter cells (identical to each other and parent cell)
|
|
Haploid vs. Diploid
|
Haploid: # of unique chromosomes (n=3)
Diploid: organisms that contain 2 copies of each chromosome (2n=6) |
|
Homologous
|
Diploid cells are: Homo - same type and same genes |
|
Chromosome Duplication
|
Results in 1 chromosome consisting of 2 sister chromatids, sister chromatids will be separated during mitosis (which doesn't change ploidy).
|
|
Ploidy
|
The number of sets of chromosomes in a cell.
|
|
All Cells Are Either In:
|
M Phase: Mitosis and Cytokinesis
- division of genetic material and organelles to 2 new cells.
|
|
Cell Cycle
|
Go: subphase of G1 were cells don't divide for long time
G1: normal cell growth and function S: synthesis (dna replication) G2: preparation for division Mitosis: Division of identical genetic material Cytokinesis: cytoplasm, cell membrane and other organelles are divided between daughter cells. |
|
How does the cell cycle run?
|
Most cells exist in function in G1, until given signal to replicate DNA.
Afters S phase, there are two identical sister chromatids for every chromosome. Mitosis divides those identical chromatids into 2 new cells. III (1 chromsome) -> XXX (duplication into s. chromatids) -> XXX (lineup in nucleus) -> III + III (divide into 2 cells) |
|
Difference between II II II II and XX XX XX XX
|
First one shows diploid cells (they are paired but not duplicated)... second one (shows duplicated pairs).... Each X is split up into new cell
|
|
Prophase
|
C. condense and appear as two sister chromatids.
Cytoskeleton is dissambled and spindle begins to form |
|
Metaphase
|
All C. are aligned at equator of cell called the metaphase plate, chromosomes are attached to opposite poles and are under tension.
|
|
Anaphase
|
sister chromatids are split and individual chromosomes are freed and pulled to opposite poles.
Spindle poles move apart |
|
Telophase
|
C. clustered at opposite poles decondense and nuclear envelopes re-from around chromosomes.
|
|
Phosphorylation
|
Addition of a phosphate functional group to a protein that changes shape, function and charge of protein. Done by kinase enzymes, and phosphatase removes a phosphate group.
|
|
Cyclin
|
protein that is only made during specific times on substages in cell cycle
|
|
Cdk
|
Cyclin dependent kinase - only functions when in complex with cyclin. They phosphorylate a lot of other proteins and enzymes to advance cell cycle
|
|
How does cell cycle advance?
|
Cyclin is made during G2, which binds to Cdk to advance to M. It then degrades and the cycle repeats. High cyclin = high Cdk phosphorylation = high division rate.
|
|
Stopping the cell cycle?
|
Cell can't go in "reverse", checkpoints, are signals in c.c. where cells wait for signals to proceed
|
|
3 major checkpoints
|
G1/S checkpoint: growth factors, nutrition state, size of cell
G2/S checkpoint: replication completed, DNA integrity is okay Spindle checkpoint: chromosomes attached to metaphase plate |
|
Cancer
|
Regulation of cell cycle is disrupted that begins with a tumor (mass of cells with uncontrolled cell division). The proteins that act as checkpoint don't work properly, usually due to mutation in genes that make protein.
|
|
2 types of proteins
|
tumor suppressing: STOP. Prevent cell division by acting at checkpoints.
proto-oncogene: START. promote cell division by failing to act checkpoints. |
|
Mutations of those proteins
|
P.O. - produces oncogenes that cause cancer by stimulating cell division where it shouldn't occur. (its always going).
T.S. - cause cancer by failing to block cell division in cells taht are damaged or are in no condition to divide (its always going). |
|
p53
|
Tumor suppressing
- dna damage causes p53 to become phosphorylated and prevents its (degradation)... which causes a build up of p53. - accumulation of p53 int he nucleus produces cell division inhibitors. (could act on protein that stops cyclin/cdk binding |
|
What can pass through membrane and what can't?
|
Small hydrophobic molecules can pass directed through.
Proteins have to be secreted by exocytosis (done w/ vesicles). which fuses with the plasma membrane. |
|
Why does cell signaling happen?
|
Allows us to have multicellularity and organize to form tissues, etc..
|
|
5 Cell signaling outputs
|
1. change cell shape.
2. change cell migration 3. change cell division/proliferation/growth 4. change cell function 5. change gene expression, which changes proteins made... DNA -> RNA -> protein |
|
Direct Contact
|
Tight junction, adhesive junction, or a gap junction
|
|
Gap Junction
|
When cells are in close contact with each other they have perfectly lined up pores that are able to transport things right to them.
|
|
Paracrine & Autocrine Signaling
|
short range signaling
Paracrine (next door) Autocrine (to itself) ie: growth factors Produce short lived, local effects. |
|
Endocrine Signaling
|
Long - range signaling
ie: through blood, hormones Live longer and produce effects elsewhere. |
|
Synaptic Signaling
|
A kind of paracrine signaling
ie: neurotransmitters Transports through a small synaptic gap to the target cell. |
|
LIgand
|
small molecules or protein that transports a signal that binds to the receptor
|
|
Amino Acids and Phosphorylation
|
Only 3 AA can be phosphorylated (ser, thr, tyr) and it causes a protein conformational change.
|
|
Nuclear Hormone Signaling
|
Intercellular signaling
Small, hydrophobic molecules go right through membrane to cause cellular response... it binds to a n. hormone receptor (causes conformational change) that bind to dna to help rna pol. transcribe, make it not transcribe, or know how much to transcribe. |
|
N.H.S. Receptor
|
Has 3 domains:
ligand bind domain activation domain (inhibitor or no inhibitor) dna binding domain |
|
Extracellular Receptors
|
All integral membrane proteins (permanently attached to membrane).
Ligand does not enter cell to change signal Ligand binding causes conformational change, which changes activity of receptor. |
|
Channel Linked Receptor
|
AKA: Ligand - gated channel
Channel contains receptor specific ligand. Ligand binding -> receptor -> conformational change (opens channel)
|
|
Enzyematic Receptor
|
phosphorylation and their substrates are found in the intercellular space (cytoplasm).
ie: insulin, growth factors 2 types (both kinases): RTK and Ser/Thr Kinase Ligand binding causes receptors to dimerize which cause them to phosphorylate each other (auto-phosphorylation). Other proteins bind to P group on cytoplasmic domain of receptors and can become phosphorylated which causes a cellular response |
|
Secreted proteins
|
Not phosphorylated
|
|
Ras
|
|
|
RTK
|
receptor Tyr kinase pathway
|
|
Shutting down RTK pathway
|
1. activated Ras eventually hydrolyzes GTP to yield GDP.
2. active receptor (bound to ligand) is eventually endocytosed (expelled from cell), which makes a vesicle that contains the receptor that can be recycled or degraded. |
|
GPCR Signaling
|
Gene Protein Coupled Receptor
|
|
GPCR Structure
|
7 transmembrane domains
extracellular ligand binding domain intercellular domain that makes contact with LARGE G-protein |
|
GPCR Process 1. Ligand Binding to GPCR |
Causes a conformational change
|
|
GPCR Process 2. Activation of G protein |
Heterotrimer - alpha - GDP, beta, gamma (made of three things).
Alpha binds to GTP and dissociates from beta and gamma and activates 2nd messengers (beta and gamma work together to do that too). |
|
GPCR pathway
|
Ligand - GPCR - Alpha-GTP - adneyl cyclase - cAMP - PKA - glycogen - glucose
|
|
Problem: Diverse outputs from 1 signal
|
Different cells respond differently to same signal because different cells have different signaling specific pathway member present. Also, not all cells have same proteins present so some of the options some cells have some cells don't even have.
|
|
Operator
|
Binding sit for other proteins called (repressors and inducers) before the promoter region that inhibit RNA pol to binding site. And help with make sure not all cells are transcribing same genes.
|
|
How do you make intermediate amount of protein
|
Regulate frequency of transcription
|
|
Bacteria in Low and High Trp
|
Low Trp - bacteria make their own (encoded enyzmes make Amino acids)
High Trp - bacteria don't make their own |
|
Operon
|
Cluster of co-regulated genes (includes operator and promoter) that all have same promoter/operator.
|
|
How does Trp operon work?
|
It encodes Trp synthesis pathway components (that synthesizes Trp together).
Trp turns Trp operon off so it won't produce it. Uses a TRp repressor which conformationally changes and binds to operon to inhibit RNA pol. binding. No Trp -> Trp operon turns on (bacteria must synthesize own Trp)
|
|
Lac Operon
|
encodes lactose catabolism pathaway components. Includes a CAP binding domain (CAP-Operator- Promoter - Genes in that order)
|
|
Lac Operon On/Off
|
On: Lactose is used (catabolism breaks it down)
Off: Lactose is not used (it is ignored) |
|
Lac Presence/Not
|
If lac is present, lac operon is expressed so lac can be broken down
|
|
Glucose Presence
|
Lac operon is repressed. CAP is an inducer that is active when bound to cAMP... it binds to the CAP region and is necessary for lac operon expression. When glucose is present, cAMP levels go down which makes CAP not active and causes it not to bind which turns lac operon off.
|
|
Cell Fate |
It changes and is driven by different combinations of transcription factors. |
|
RNA Splicing |
Alternative splicing causes multiple gene products from different variations of mRNA and proteins |
|
Enhancers |
Each gene has multiple enhancers located close to promoter or far away, or even are in introns. Each enhancer contains TF binding sequence. |
|
2 kinds of TF |
general (all cells, help RNA pol. work) - assemble to promoter Activators/repressors - cell type specific, bind to enhancers, produce combos that lead to differences in different cell types. |
|
How can enhancers far away affect gene sequence? |
a loop like figures forms with one specific TF from RNA pol. holoenzyme to activate transcription |
|
Nucleosomes |
organize dna and regulate genes by having histone proteins that can bind tightly to dna and this can limit access of ran pol to promoters and TF to enhancers. Dense nucleosomes -> repressive to transcription |
|
2 major kinds of post translational modificiation |
acetylation (-) makes it looser due to negative phosphates in dna/increase gene expression methlyation (+) makes it tighter and decreases gene expression.
|