Term
| cells can control what genes are expressed and what genes are not expressed |
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Definition
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Term
| In all organisms, regulation allows adjustment of the level of ______ synthesis to meet the needs of the cell/organism |
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Definition
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Term
_______ allows differential expression of genes
1. Developmental pathways
2. Specialization of cell and tissue types |
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Definition
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Term
Transcription
Degrade mRNA
Translation
Degrade protein
Inhibit protein function
these are all ways that genes are ____ |
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Definition
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Term
| All the genes in the metabolic pathway are under the same “controller” – the ___ concept |
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Definition
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Term
| several genes can share the same _____ |
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Definition
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Term
| The regulatory “switch” is a segment of DNA called an ______ usually positioned within the promoter |
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Definition
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Term
| An ____ is the entire stretch of DNA that includes the operator, the promoter, and the genes that they control |
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Definition
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Term
operons can be ____ regulated.
operon is switched off by the regulatory (repressor) protein. |
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Definition
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Term
| operons can also be _____ regulated – operon is switched on by the regulatory protein |
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Definition
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Term
| negative regulation can be either ____ or ____ |
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Definition
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Term
_____ type of negative regulation. gene expression is usually on. Is turned off when a repressor binds to the operator.
Example: the trp operon |
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Definition
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Term
type of negative gene regulation.... _____ gene expression is usually off. Is turned on when the repressor is inactivated. ____ inactivates the repressor.
Example: the lac operon |
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Definition
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Term
| A small percentage of any lactose present isomerizes to _____ |
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Definition
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Term
| A molecule called an _____ INactivates the repressor to turn the lac operon on |
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Definition
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Term
| Lactose absent, repressor active, operon _____ |
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Definition
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Term
| _____ enzymes usually function in catabolic pathways; their synthesis is induced by a chemical signal |
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Definition
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Term
| Regulation of the trp and lac operons involves ____ control of genes because operons are switched off by the active form of the repressor |
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Definition
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Term
| Tin positive regulation the regulatory protein acts directly on the operon to switch _____ gene transcription. |
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Definition
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Term
| if lactose and glucose is also present, the rate of lac operon transcription will be ____ |
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Definition
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Term
| But if lactose is present AND glucose is low, then ____accumulates. |
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Definition
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Term
| Active CAP = increased rate of transcription of _____ operon genes |
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Definition
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Term
| in positive regulation Activated CAP attaches to the promoter of the lac operon and increases the affinity of RNA polymerase, thus accelerating ____ |
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Definition
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Term
| When glucose levels increase, ____ detaches from the lac operon, and transcription returns to a normal rate |
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Definition
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Term
| Eukaryotic gene expression can be regulated at ______ stage |
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Definition
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Term
| In multicellular organisms gene expression is also essential for cell specialization, i.e cells regulate _____ as well as when genes are expressed |
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Definition
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Term
| muscle cell DNA = _____ cell DNA |
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Definition
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Term
| Errors in gene expression can lead to diseases including _____ |
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Definition
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Term
Chromatin
Transcription
mRNA processing
Degrade mRNA
Transport of mRNA out of nucleus
Translation
Post-translational protein modifications
Degrade protein
Inhibit protein function
all of these ways are also ways that ____ can regulate gene expression |
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Definition
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Term
| Genes within highly packed _____chromatin are usually not expressed |
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Definition
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Term
Chemical modifications to histones and DNA of chromatin influence both chromatin structure and gene expression
_____lation
____lation
_____lation |
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Definition
acetylation
methylation
phosphorylation |
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Term
| _______lation of histone tails promotes loose chromatin structure that permits transcription |
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Definition
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Term
| the addition of phosphate groups (phosphorylation) next to a methylated amino acid can also loosen ______ |
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Definition
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Term
| The addition of methyl groups (methylation) can condense ______ |
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Definition
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Term
| Methylation of DNA prevents its ______ |
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Definition
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Term
| DNA methylation is the addition of a methyl group to the base ____ |
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Definition
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Term
| the _______ code hypothesis proposes that specific combinations of modifications, as well as the order in which they occur, help determine chromatin configuration and influence transcription |
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Definition
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Term
according to histone code: Methylation of histone or of DNA usually turns a gene ______
Acetylation of histone usually turns a gene _____ |
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Definition
methylation = OFF
acetylation = ON
phosphorylation = DEPENDS |
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Term
DNA ____lation can cause long-term inactivation of genes in cellular differentiation
It also In genomic imprinting, ____lation regulates expression of either the maternal or paternal alleles of certain genes at the start of development |
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Definition
| methylation & methylation |
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Term
| _______ modifications do not alter DNA sequence. |
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Definition
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Term
Chromatin modifications do not alter DNA sequence. However, they may be passed to future generations of cells
This type of inheritance of traits transmitted by mechanisms that do not directly involve the nucleotide sequence is called |
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Definition
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Term
| segments of noncoding DNA that critically help regulate transcription by binding certain proteins |
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Definition
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Term
| Control elements for the initiation of eukaryotic transcription can be located near ____ or far ______from the actual DNA sequence to be transcribed. |
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Definition
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Term
A transcription _____ is a protein that binds to an enhancer and stimulates transcription of a gene
Bound ones cause mediator proteins to interact with proteins at the promoter |
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Definition
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Term
| Bending the DNA by proteins enables ________ to influence a promoter hundreds or thousands of nucleotides away. |
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Definition
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Term
| “Activators” bind to enhancer DNA sequences and then the _____ proteins then the general transcription factors. |
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Definition
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Term
| Some transcription factors function as _______, inhibiting expression of a particular gene |
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Definition
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Term
| A particular combination of ____ elements can activate transcription only when the appropriate activator proteins are present |
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Definition
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Term
| Unlike the genes of a prokaryotic operon, each of the coordinately controlled eukaryotic genes has its own _____ and control elements |
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Definition
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Term
| The life span of mRNA molecules in the cytoplasm is a key to determining ______ synthesis |
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Definition
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Term
| _____yotic mRNA is more long lived than ____karyotic mRNA |
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Definition
| eukaryotic lives longer than prokaryotic |
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Term
| Degradation of mRNA usually begins with shortening the _______ |
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Definition
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Term
The initiation of translation of selected mRNAs can be blocked by regulatory proteins that bind to sequences or structures of the mRNA
Within 5’ UTR, these proteins can prevent _______ attachment |
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Definition
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Term
| translation of all mRNAs in a cell may be regulated ______ |
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Definition
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Term
| Many _____ must be processed before becoming active proteins. |
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Definition
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Term
| Protein degration often involves a small protein called ______ which is added to the larger protein. This is the “kiss of death.” The protein then enters a proteasome which is the “death chamber.” |
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Definition
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Term
| It is important that proteins be _____ when their usefulness is over or their function fulfilled |
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Definition
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Term
| Noncoding _____ play multiple roles in controlling gene expression |
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Definition
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Term
A significant amount of the genome may be transcribed into _______
they also regulate gene expression at two points: mRNA translation and chromatin configuration |
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Definition
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Term
_______ are small single-stranded RNA molecules that can bind to mRNA
These can degrade mRNA or block its translation |
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Definition
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Term
Multicellular organisms depend on cell _______ for:
Development from a fertilized cell
Growth
Repair |
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Definition
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Term
| Cell division in unicellular organisms = _____ |
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Definition
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Term
Make copies of existing cells =_______
Diploid
Identical
Somatic |
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Definition
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Term
| __________= division of the cytoplasm in either mitosis or meiosis |
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Definition
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Term
Make gametes = ________
Haploid
Different from original cell
Gametes |
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Definition
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Term
| _______= the linear DNA molecule + its associated protein also composed of chromatin. |
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Definition
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Term
| Where the sister chromatids are most closely attached is at the ____ |
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Definition
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Term
Cell growth
Replication of DNA
Preparation of chromosomes for cell division
all of these happen in the ____ phase of cell cycle |
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Definition
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Term
Interphase (about ______% of the cell cycle) has three subphases:
G1 phase (“first gap”)
S phase (“synthesis”)
G2 phase (“second gap”)
The cell grows during all three phases, but chromosomes are duplicated only during the ____ phase |
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Definition
| 90% of cell cycle is interphase. chromosomes are only duplicated in the S phase |
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Term
Protein structure associated with centromere
Attachment point for microtubules of the spindle
these describe the ____ |
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Definition
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Term
| In ______phase, sister chromatids separate and move along the kinetochore microtubules toward opposite ends of the cell |
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Definition
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Term
| : At which end do kinetochore microtubules shorten during anaphase? |
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Definition
| at the end of which is attached to the kinetochore |
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Term
| The results of fusing cells at two different phases of the cell cycle suggest that molecules present in the cytoplasm of cells in the ____ or ____ phase control the progression of phases. |
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Definition
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Term
| the frequency of cell division depends on the ______ |
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Definition
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Term
G1: stay or leave?
S: to replicate or not to replicate?
G2: stay or leave?
Mitosis: Are we there yet?
these are all controlled by the _____ signals in the _____ |
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Definition
| chemical signals in the cytoplasm |
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Term
| the cell cycle control system has specific ______ where the cell cycle stops until a go-ahead signal is received |
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Definition
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Term
restriction point (mammals)
If “go-ahead” signal received at _____, then cell completes entire cycle
If not, cell exits cell cycle and switches to non-dividing state |
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Definition
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Term
| ________ are important intrinsic regulators of the cell cycle...which are classified as cyclin-dependent kinases (Cdks) |
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Definition
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Term
| Cyclin-dependent kinases need another molecule called ______ in order to be active. |
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Definition
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Term
| Cyclin + Cdk =_______ This protein complex triggers a cell’s passage past the G2 checkpoint into the M phase |
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Definition
| MPF (maturation-promoting factor) |
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Term
| Phosphorylate proteins to start mitosis and also activates proteases that degrade cyclins. |
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Definition
| MPF..maturation promoting factor |
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Term
_______ can be influenced by internal & external factors:
nutritional status
hormones
chemical signals |
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Definition
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Term
internal factor example occurs At ________phase checkpoint.
Anaphase does not occur until all kinetochores have been attached to microtubules. Molecular signals are released that cause the sister chromatids to remain attached together until all kinetochores have been attached. |
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Definition
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Term
| this is an example of an ____ factor checkpoint: Growth factors are proteins released by certain cells that stimulate other cells to divide |
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Definition
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Term
| Another example of external signaling is _______-dependent inhibition, in which crowded cells stop dividing |
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Definition
| density dependent inhibition |
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Term
| Most animal cells also exhibit ______ dependence, in which they must be attached to a substratum in order to divide |
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Definition
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Term
Cancer cells lose control over cell ______
- They can migrate to other parts of the body
- They often lose density and/or adhesion dependence. |
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Definition
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Term
| _________ cells don’t depend on response to these signals like growth factors. Instead they grow almost continuously. |
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Definition
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Term
| A _______ is a large mass of cells. |
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Definition
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Term
| ______ tumors resemble the tissue they grow from, grow slowly, and remain localized. they are not cancerous |
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Definition
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Term
_________ tumors do not resemble the tissue they grow from and may have irregular structures.
Cancer cells can invade surrounding tissue and travel through the bloodstream or lymph system. |
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Definition
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Term
| _______, or spreading, can cause organ failure and is hard to treat. |
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Definition
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Term
__________ genes
Encode proteins that inhibit abnormal cell division
genes that help prevent uncontrolled cell growth
Mutations of these DO contribute to cancer |
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Definition
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Term
Genes that normally regulate cell growth and division during the cell cycle
Includes genes for growth factors, their receptors, and the intracellular molecules of signaling pathways
these are one of the two types of genes that are associated wtih _____ |
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Definition
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Term
Normal genes involved in controlling cell division. They do not cause cancer.
these are called |
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Definition
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Term
| _______ are genes which no longer control cell division properly. |
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Definition
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Term
| Mutations that make a proto-oncogene excessively active convert it to an ______, which may promote excessive cell division and cancer |
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Definition
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Term
| if norml cell signaling is interrupted... gene thats involved in signal cascade that produces protein which stimulates cell cycle |
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Definition
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Term
| _______ gene – a tumor suppressor gene. |
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Definition
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Term
| ______ gene prevents a cell from passing on mutations due to DNA damage |
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Definition
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Term
| At the DNA level, a cancerous cell is usually characterized by at least one active oncogene and the mutation of several __________ genes |
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Definition
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Term
Chromosomes may ______ genes before separating
Process = crossing over
Produces additional genetic diversity |
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Definition
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Term
| In a diploid cell, every chromosome has a ________ |
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Definition
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Term
| In _______ the sister chromatids separate. Each cell gets one of the sister chromatids from each homologue |
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Definition
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Term
| In _______ each cell gets only one of the sister chromatids from only one of the homologues |
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Definition
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Term
| Meiosis I is preceded by ____phase, when the chromosomes are duplicated to form sister chromatids |
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Definition
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Term
| _____ in prophase 1= homologous chromosomes loosely pair up, aligned gene by gene |
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Definition
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Term
| crossing over and synapsis all happen in ______ of meiosis 1 |
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Definition
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Term
| group of 4 chromosomes is a |
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Definition
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Term
| Each tetrad usually has one or more _________, X-shaped regions where crossing over occurred |
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Definition
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Term
| do the sister chromatids in anaphase 1 stay attached? |
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Definition
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Term
| Metaphase 2= Because of crossing over in meiosis I, the two sister chromatids of each chromosome are no longer ______ |
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Definition
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Term
| At the end of meiosis 1 & 2, there are four daughter cells, each with a _____ set of unreplicated chromosomes |
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Definition
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Term
| the _______ cortex consists of protein strands joining duplicated chromosomes between sister chromatids |
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Definition
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Term
| = manipulation of organisms or their components to make products |
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Definition
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Term
| Using bacteria to produce copies of eukaryotic genes = |
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Definition
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Term
| gene cloning Makes use of ________= small circular DNA molecules found in bacteria. These are separate from the bacterial chromosome. |
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Definition
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Term
| the plasmid is an example of a cloning ________ |
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Definition
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Term
| How do you isolate the specific gene that you want to clone from the vast number of genes on all the chromosomes? |
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Definition
DNA library....make a bunch of copies of DNA
or genomic library... chop up all the DNA and grow them in plastids |
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Term
________ enzymes =
Needed to make DNA fragments for cloning
Needed to “open up” the plasmid so the DNA fragments can insert.
= Endonucleases found in bacterial cells |
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Definition
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Term
| Bacterial restriction enzymes cut DNA molecules at specific DNA sequences called __________ |
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Definition
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Term
| The most useful restriction enzymes cut DNA in a staggered way, producing fragments with ______ ends |
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Definition
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Term
Seal the fragment to the plasmid with _____
the superglue! |
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Definition
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Term
| in cDNA libraries Bacteria can’t splice out the _____. so its Useful to have the “processed” DNA |
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Definition
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Term
| the clone that contains the gene that you are seeking i.e. the |
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Definition
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Term
| in order to screen for the beta globulin gene you need a _____ acid probe |
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Definition
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Term
You have to have some idea of at least part of the sequence of the gene you are seeking
Work backwards from amino acid sequence of the protein
Use known genes from related species
Can be DNA or RNA, but is single stranded
Probe is labeled so you can track it
all these need to happen in order to screen for the |
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Definition
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Term
| Gene will insert at the restriction site and therefore be near the______ because genes need these to be expressed |
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Definition
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Term
| To sequence an entire _____ the DNA is first cut into fragments about 500 base pairs (bp) long. |
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Definition
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Term
The Human Genome Project used two approaches:
_____sequencing &
_______ sequencing |
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Definition
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Term
| in _______ sequencing, short marker sequences are identified—ensuring that every DNA fragment would have a marker. |
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Definition
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