Lecture 1 Flashcards
(115 cards)
1
Q
plasma membrane
A
communication with environment
2
Q
cytoplasm
A
protein synthesis, metabolic pathways
3
Q
nucleus
A
DNA synthesis, transcription, splicing
4
Q
mitochondria
A
energy production, metabolic pathways
5
Q
lysosomes
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protein and carbohydrate degradation
6
Q
peroxisomes
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disposal of peroxide, fatty acid metabolism and other metabolic pathway
7
Q
secretory and endocytic organelles
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protein transport out of and into cells
8
Q
Multicellular organisms are made of – that are organized to carry out specialized functions
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different types of cells
9
Q
odontoblast –
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dentine production
10
Q
ameloblast
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enamel production
11
Q
The specialized cells all derive from a common – cell (the fertilized egg) through the process of development, which is a complex series of events involving both cell division and differentiation into particular cell types
A
progenitor
12
Q
stem cells they have the ability to divide to produce more stem cells called –
A
self-renewal
13
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stem cells can – into specialized cell types
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differentiate
14
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– cells can give rise to all embryonic tissues including germ cells (e.g. embryonic stem cells)
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Pluripotent stem
15
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– can give rise to all cell types in a tissue (e.g. hematopoietic stem cells
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Multipotent stem cells
16
Q
Manipulation of – (embryonic or adult stem cells) offers great potential for therapeutic organ replacement, e.g. teeth.
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stem cell differentiation
17
Q
– are the most versatile components of cell
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Proteins
18
Q
act as –to synthesize or degrade cellular components
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enzymes
19
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proteins act as – to provide shape, organization and stability to cells
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structural components
20
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T/F: proteins act as carriers and motors to move molecules within and between cells, regulators of different cellular processes,
A
true
21
Q
Proteins are encoded in DNA as genes that contain information for the – of each protein
A
structure and expression
22
Q
in addition to mRNA, DNA also encodes – used in protein synthesis and a variety of other non-coding RNAs
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ribosomal and transfer RNAs
23
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decoding of the DNA into proteins involves – RNA
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messenger
24
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Synthesis of RNA from DNA occurs by the process of –
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transcription.
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Regulation of transcription determines what genes are expressed --, at what time, and at what amounts
in what cells
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transcription dictates cell --
type and function.
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In eukaryotic cells, newly transcribed RNA must be -- to the cytoplasm in order to be decoded into protein by ribosomes and tRNA.
processed and exported
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central dogma of molecular biology
DNA --> RNA --> protein
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Proteins are linear polymers of --
20 different amino acids
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An individual cell contains thousands of different proteins, each with a -- of amino acids
unique sequence
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each of these proteins has a distinct three-dimensional structure that specifies its function, and the 3D structure is determined by the --.
linear sequence of amino acids
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amino acid is an -- bonded to an amino group, a carboxyl group, a hydrogen, and one of twenty different side chains (R)
alpha carbon
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determines the properties of the amino acid.
side chain
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Hydrophilic amino acids (acidic, basic and uncharged) are generally found at --
the surface of water-soluble proteins or protein domains.
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Hydrophobic amino acids (linear, branched and aromatic) are generally found in the -- or in lipid-associated regions of membrane proteins.
interior of water-soluble proteins
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The sulfhydryl group (SH) of a cysteine can form a -- with the SH group of another cysteine.
covalent disulfide bond
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T/F: Disulfide bonds can occur within a protein or between proteins
true
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its R group is a hydrogen making it the smallest amino acid
glycine
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Glycine causes little -- and allows structural flexibility
steric hindrance
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in proline, the amino group is --, forming a ring structure that makes proline rigid
covalently joined to the side chain
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Amino acids are covalently joined together in a protein by a -- involving the carboxyl group of one amino acid and the amino group of the next.
peptide bond
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By convention peptides are written
N --> C
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peptide bonds have -- character and thus is rigid and planar.
partial double bond
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The carbonyl oxygen and the amide hydrogen on either side of a peptide bond are usually in a --
trans configuration (opposite sides of peptide bond)
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Free rotation around -- (except proline) allows high degree of conformational flexibility.
C-Calpha and Calpha-N bonds
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Proteins fold into the thermodynamically most stable conformation called --
native conformation
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Native conformation is determined by interactions between --
amino acid residues.
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linear sequence of amino acids.
primary
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localized organization of aa usually close to each other in sequence
secondary
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secondary structure mostly stabilized by --
H bonds
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alpha helix is a regular coil structure stabilized by hydrogen bonds between the peptide bond carbonyl group and the peptide bond --
amide four residues towards the carboxy-terminus
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R groups of alpha helix
project outwards
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-- interrupts alpha helix
proline
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beta strands are -- of amino acids.
linear, extended stretches
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Lateral (side-by-side) association of beta strands form --
beta sheets
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Beta sheets strands are joined by H bonds between
carbonyl groups on one strand and amide groups on other
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strands of beta sheets are --
parallel or antiparallel
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R groups of beta strands
project up or down
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beta turns: -- stabilized by hydrogen bonds between carbonyl group of first residue and amide group of last residue
3-4 aa U-shaped turn
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-- are combinations of 2° structures
Structural motifs
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protein's overall 3D conformation
tertiary
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-- can involve interactions between amino acids as far away from each other in primary sequence
tertiary structures
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tertiary interactions
Stabilized by non-covalent interactions – H-bonding, electrostatic (binding of oppositely-charged side chains), hydrophobic interactions (in interior of globular protein), van der Waals forces due to close packing of atoms, sometimes S-S
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oxygen storing molecule in muscle
myoglobin
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myoglobin's amino acids are complexed with an iron-containing heme group that is necessary for --
oxygen binding
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3D structure of protein made up of multiple subunits
quarternary
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T/F: Quaternary held together by same forces as 3D structure
true
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Each subunit of hemoglobin has a structure very similar to myoglobin, even though the -- are quite distinct
primary sequences
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The quaternary structure of hemoglobin allows -- which makes hemoglobin more suited for oxygen delivery to tissues than myoblobin
cooperative binding and dissociation of oxygen
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This type of effect on substrate (oxygen) binding by an interaction at another site (binding to another hemoglobin chain) is known as --
allosteric effect
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Many proteins larger than 150 amino acids are organized into --.
structurally distinct domains
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These domains are usually 100-150 amino acids in length and are folded into --
distinct 3D structures
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Domains in proteins are linked by -- of the polypeptide chain.
intervening segments
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For example, transcriptional activators are often organized into --
DNA-binding and transcriptional activation domains.
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Many -- are associated with the lipid bilayer of cellular membranes
proteins
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embedded (pass through) the lipid bilayer
integral membrane proteins
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The region of the protein that spans the membrane (membrane-spanning domain) is usually an --
alpha helix composed of hydrophobic amino acids
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The protein regions on either side of the membrane use the same organizing principals as --
soluble proteins
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Integral membrane proteins are often -- on the lumenal (non-cytoplasmic) domains
glycosylated
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Sugar chains are covalently linked to the NH2 of --(“N-linked”)
asparagine
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Sugar chains are covalently linked to the OH groups of --(“O-linked”).
serine and/or threonine
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Some integral membrane proteins do not have hydrophobic transmembrane domains but instead have covalently attached lipids that -- and act as anchors.
insert into the bilayer
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--are associated with the surface of membranes but do not extend into the hydrophobic core of the bilayer.
Peripheral membrane proteins
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Association of peripheral membrane proteins usually involves interaction with a transmembrane protein and/or with the --
hydrophilic head groups of the membrane lipids.
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Genes are the basic unit of --
inheritance (Mendel, 1860)
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Genes are arranged into -- that are distributed to daughter cells during mitosis and segregated into gametes during meiosis
chromosomes
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Heritable variations between individuals in a species are due to changes in the genes, called -- in the DNA sequence of the gene
mutations
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If the mutation occurs in the -- then it can be passed on to offspring
germ-line
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If the mutation occurs in cells other than the germ-line then it is not passed on to offspring but it is passed on to progeny of the mutant cell in the individual as the cell divides.
somatic mutation
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Somatic mutations that affect -- can lead to cancer
cell growth control
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Many common congenital malformations (such as cleft lip/palate) and common adult diseases such as diabetes, heart disease and cancer are due to the combined effects of mutations in multiple genes (polygenic), often combined with environmental factors.
multifactorial
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different forms of a gene.
alleles
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The normal allele of a gene is often referred to as the
wildtype allele
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One copy of each chromosome (1N).
haploid
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Humans are formed by the union of a -- and 22 other chromosomes (autosomes) with a haploid egg carrying an X chromosome and 22 autosomes
haploid sperm carrying 1 sex chromosome (X or Y)
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If an individual has the same allele on both chromosomes then the individual is
homozygous
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Human males have only one copy of alleles on the Y chromosome and this is referred to as
hemizygous
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different alleles on the two chromosomes.
heterozygous
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the entire set of an organism’s genes
genotype
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But in practice genotype is often used to refer to --
a single gene.
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the function and physical appearance of an organism
phenotype
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In practice phenotype is often used to refer to the -- of a single gene
physical and functional consequences
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both alleles have to be mutant in order to see a mutant phenotype.
recessive mutation
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Recessive mutations normally cause inactivation or elimination of a gene/protein.
loss of function
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mutant phenotype is present in heterozygous individual.
dominant mutation
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haplo-insufficiency: If -- does not produce enough protein to prevent disease then an individual with one normal allele and one inactivated allele would develop disease and the mutation would be designated as dominant
one normal copy of a gene
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dominant negative: If the mutant allele produces a form of the protein that interferes with the function of the normal protein, often by --, then this could cause disease in a heterozygote.
binding to the normal protein
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If the mutant allele produces a protein with new, or increased levels, of function , then this could cause disease in a heterozygote.
dominant-positive or gain-of function
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mitochondrial DNA encodes genes for some proteins involved in oxidative phosphorylation and --
protein synthesis in the mitochondrion
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Mutations in mitochondrial DNA can cause -- called mitochondrial disorders
inherited disease
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Prions are infectious agents, consisting only of protein, that have the ability to --
reproduce within cells
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prions represent an amazing exception to the dogma that infectious agents (like viruses, bacteria, etc) require -- for reproduction
nucleic acids
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Prions are abnormally folded forms of -- and convert the endogenous form into the abnormal form
endogenous protein that can form aggregates
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The abnormal form of prions is in a mostly -- while the normal form is mostly a helical.
b -sheet conformation
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The normal and abnormal prions forms have exactly the same --, but different --
same amino acid sequence and different secondary and tertiary structures.
