cell bio final lpm

mutation

randomly produced, permanent change in the nucleotide sequence of DNA

effects of mutations on proteins can be

loss of function, altered function, or no change in function

beneficial mutation

evolution from chimp to human

detrimental mutation

extinction or genetic disorder

do all mutations cause a change or significant effect on their functional product

no FALSE

mutations within a gene can

• change info of that gene

• alter the processing (cap, tail, and or splicing) of RNA

• change stability, activity, location, or interactions of its rna product and or encoded protein

mutations within dna intergenic regions (w/ regulatory regions)

how much, when, and where a gene is expressed can b affected by a mutation in DNA sequences that regulate the gene’s activity such as promoter, silencer, and enhancer

• regulation of expression affected by intergenic regions

mutations within dna intergenic regions (not containing regulatory regions)

• will not result in an effect but could have an impact on various dna-related processes

  • can occur within regions of dna such as ori’s and centromeres that could effect dna replication and aspects of cell division

    • can occur within regions of dna that contain binding sites for chromatin-remodeling complexes, resulting in altered chromatin structure, and affect gene expression

mutations within a gamete cell EGG SPERM will potentially be transmitted or passed on to ??

offspring (meaning every cell that makes up the offspring will contain the mutation)

mutation within a somatic cell (the cells that make up the body) will be passed on or not?

not passed on to the offspring BUT will potentially effect that individual that has the mutation.

point mutation

mutation that changes a single or few nucleotide or base pairs

how do point mutations occur

mistakes during DNA repliation and repair; they can change the nucleotide sequence within a gene

base substitution

different nucleotide is put in the place of what should be the corret/original one

how can base substitutions be

silent, missense, nonsense

what do base substitutions do

add or delete nucleotides from the gene

addition or deletion of single base results in

frameshift

base substitution is when

one base is wrongly paired w another base during dna replication

neutral mutations

base pair subs that have little or no impact on protein function

ex of a drastic base pair substitution

sickle cell anemia

silent mutation

has no effect on the amino acid sequence ; new codon translate into the same amino acid

missense mutation

codes for an amino aicd, but translates into a diff amino aicd; changes 1 amino acid

NONSENSE mutation

base sub that changes an amino acid codon into a stop codon

what does a nonsense mutation DO

causes translation to be terminated prematurely and almost always leading to a nonfunctional protein

frameshift mutations involve?

addition/ insertion ; or deletions/loss of nucleotides in a gene

are frameshift mutations more serious or less than base-pair substitutions

more serious, bc they can result in many wrong amino acids and thus the production of a nonfunctional protein.

a mutation can alter the sequence within a promoter and affect the rate of transcription:

may enhance or inhibit transcription

mutations in _________________ are not likely to have an effect but still possible

non coding intergenic regions

mutation can occur in other regulatory regions which will

alter pre-rna processing mechanisms or ability of mRNA to be translated

effects of mutations outside of the promoter

may increase or decrease the rate of transcription

effects of mutations outside of the the transcriptional regulatory element or operator site

may alter the regulation of transcription

effects of mutations outside of hte splice sites

may alter the ability of pre-mrna to be properly spliced

efects of mutations outside of the translational regulatory elemenet

may alter the ability of the mRNA to be translationally regulated

efects of mutations outside of the intergenic region

not as likely to have an effect on gene expression

serious human disorders are due to alterations to large segments of DNA and chromosome structure resulting from the breaking and rejoining of chromosome segments

these can be caused by external sources or internal problems in the cell cycle

4 categories of chromosomal mutations

• deletion

• duplication

• inversion

• translocation

chromosomal deletion

loss of a large segment of DNA of chrommy;

can be hundreds to thousands of nucleotides and as a result potentially several genes

how severe is chromosomal deletion

lethal or serious disorder

chromosomal duplication

segment of dna that is repeated two or MORE times in a row can occur in noraml and abnormal chromosomes

• rsults in having mult copies of a gene

what is chromosomal inversion

chromosomal rearrangement that occurs when a segment of a chromosome is broken in 2 places, reversed and put back together

• alters DIRECTIONALLY a nucleotide sequence

chromosomal translocation

piece of one chromosome is broken off and becomes attached to a diff chromosome

• think crossing over that occurs in meiosis

spontaneous mutation

INTERNALLLLLLLL

no outside of the cell influence or cause

• abnormalities in internal biological processes

spontaneous mutation EX

dna polymerase making an error during DNA replication that does not get corrected/fixed

induced mutations

results from outside influence

• exposure to mutagens, chemicals, or physical agents that interact w DNA to mutations

  • can enter cell and alter DNA nucleotide sequence or structure

example of mutagens include

• chemicals (nicotine and benzopyrene)

• physical agents (x-rays and UV lights)

• viruses (papiloma hepB)

mutagens that lead to cancer are called ________________

carcinogens

all carcinogens are ____________— but not all __________ are carcinogens

mutagens, mutagens

what do mutagens do?????

alter DNA structure

some chemicals act as _________- that may be substituted into dna but tht pair incorrectly during dna replication

base analogs

other mutagens interfere with dna replication by interserting into ________ and doing?

into dna and distorting the double helix

• others cause chemical changes in bases that change their pairing properties

mutually incompatible reactions

two or more things that cannot exist, happen, or be true at the same time due to fundamental differences or direct conflict

ways to confine diff things in an eukaryotic cell

• membrane-enclosed compartments

• group enzymes into large, multicomponent complexes

prokaryotic cells usually consist of a ________— compartment enclosed by the plasma membrane.

single

eukaryotic cells are ____________- by internal membranes

sub-divided

sub-divided internal membranes include

small, membrane enclosed sacs, tubes, spheres, and irregularly shaped structures

• not much order

organelles occupy nearly ______—— the volume of an eukaryotic cell

half

in maals the endoplasmic rreticulum membrane is ________ x greater than that of the plasma membrane

20-30 times

cytosol

contains many metabolic pathways , protein synthesis, cytoskeleton

nucleus

contains main genome, dna, and rna synthesis

endoplasmic reticulum (ER)

synthesis of most lipids, synthesis of proteins for distribution to many organelles and to the plasma membrane

golgi apparatus

modification , sorting, packing of proteins and lipids for either secretion or delivery to another organelle

lysosomes

intracellular degradation

endosomes

sorting of endycytosed material

mitochondria

atp synthesis by oxidative phosphorylation

chloroplasts in photosynthetic cells

atp synthesis and carbon fixation by photosynthesis

peroxisomes

oxidative breakdown of toxic molecules

how are proteins produced

constantly

where will proteins be delivered

• specific organelle

• secreted from the cell

• stay within the cytosol

protein sorting

process of transporting a protein to its final destination where it will function

particular segment of the proteins’ amino acid sequence, the ______, will act as the sorting signal

sorting signal sequence

what does the sorting signal do

direct the protein to a particular organelle or location

synthesis of most proteins in the cell begins at the “ _____ _ “ ribosomes located in the cytosol

free floatin

exceptions of being synthesized at the free floating ribosome include

the mitochondrial and chloroplast proteins which r synthesized directly within those organelles

for interior of nucleus, er, mitochondria, chloroplasts, and peroxisomes proteins r delivered how?

directly from the cytosol

mitochondria and chloroplasts contain some of their own dna so they can..?

make their own proteins but NOT All of them alone

for the ER some proteins stay there, but most are transported by what to where

transport vesicles to golgi apparatus and then sometimes via more transport vesicles to plasma membrane, outside of cell or other organelles like lysosome

golgi aparatus gets its proteins from the ________/

ER via transport vescicle

proteins embedded within the plasma membrane inside lysosomes, or outside the cell get their proteins from?

golgi VIA TRANSPORT VESICLES

when an organelle imports a protein to its interior it must be transported acorss of thru the

phospholipid membrane

transport from cytosol into interior of nucleus occurs thru

nuclear pores

transport from cytosol into the ER, mitochondria, and chloroplasts occurs thru

protein translocators

transport from the ER to other components of the endomembrane systems occurs by _______

transport vesicles

how long are sorting signal sequences

15-60 amino acids long

will sorting signals stay or be removed after a protein has been sorted?

will be removed

____ _______ will typically keep their signal sequence

nuclear proteins

a protein that lacks a sorting signal will ________________

remain and function in the cytosol

removal of the signal sequence from an er protein converts it into ??

cytosolic protein

addition of an ER signal sequence to a cytosolic protein coverts it to a ?????

ER Protein

____ ________- are another form of targeting proteins to specific locations

signal patches

what r signal patches made up of

amino acids distant to one another in primary sequence but come close to each otehr in tertiary structure of ffolded protein

• visible/present after the protein has been folded and is not evident until that folding occurs

  • never removed as various amino acid sequences are located in different places within the protein

    • commonly used for directing proteins to NUCLEUS

what r signal sequences used for commonly

directing proteins to the nucleus

the nuclear envelope encloses the _________—- and the boundary of the nuclear compartment

nuclear dna

the nuclear envelope is comprised of two membranes

1. inner nuclear membrane

2. outer nuclear membrane

inner nuclear membrane

• contains proteins that ac as anchoring sites for the chromosomes

• nuclear lamina provides structural support for nuclear envelope

outer membrane

closely resembles the membrane of the ER (and is continuous with it)

proteins enter the nucleus through the ________?

nuclear pores

proteins that are destined to function inside the nucleus are transported thru ___________ from the ______ into the interior of the nucleus

nuclear pores, from cytosol, into interior of nucleus

how do nuclear pores function?

as selective gates or tunnels that allow molecules to enter and exit the nucleus

transport of smaller molecules and ions/atoms can occur by __________—-

passive/facilitated transport

transport of macromolecules and some smaller molecules can occur by __________-

active transport

proteins transported to the interior of the nucleus are completely synthesized in the _____________ and correctly folded into their three dimensional shape /structure before being transported.

cytosol