central dogma Flashcards
central dogma
explains the flow of genetic information, fromDNAtoRNA, to make a functional product, aprotein.
The central dogma suggest
DNA contains the information needed to make all of our proteins, and that RNA is a messenger that carries this information to theribosomes.
replication
DNA to DNA
dna polymerase
transcritption
DNA to RNA
RNA polymerase
translation
RNA to protein
ribosomes
what is dna
deoxyribose
adenine guanine timine cytosine
connected by hydrogen bonds
Each strand of DNA has a beginning and an end, called 5’ (five prime) and 3’ (three prime) respectively.
This double helix structure was first discovered by Francis Crick and James Watson with the help of Rosalind Franklin and Maurice Wilkins.
structure of DNA
DNAs are coiled up into structures calledchromosomes.
Yourchromosomesare located within the cell nucleus (chr1-22,X,Y) and mitochondria (mitochondrial chromosome).
Except for certain cells (for example, sperm and egg cells and red blood cells), the cell nucleus contains 23 pairs of chromosomes.
chromosomes
, the chromosomes (mitotic chromosome form) becomes more tightly packed during cell division and is then visible under a microscope
Human chromosome karyotyping
1842 chromosomes first observed in plant cells by Carl Wilhelm
1912 hans von viniwater reported 47 chromosomes in spermatogonia and 48 in oogina concluding sex chromosomes
1922 painter suggested humans having XX/XY
1955 humans have 46 chromomes
chimerism
A chimeric human, or human chimera, has two or more populations of genetically different cells that originated from different zygotes.
Frequently chimerism occurs spontaneously during embryogenesis. Twins fuse to get single body.
There 2 sets of cells with different chromosomes. The fusion of two person!
what is autosomes
called 22 pairs
Y chromosome contains…
SRY gene
Klinefelter syndrome
some men have more than 2 sex chromosomes many men lose Y chromosome as they age
Y chromosome is composed of
repeating DNA segments
females have one X chromosome inactivated
such inactivation stops transcription from occuring
inactivated condensed into a small dense structure called Barr Bod, barr bodies used to determine sex
Disorders of sex development (DSD)
This is an example of disorders of sex development (DSDs). A disease affecting the sex development and sex characteristics due to the chromosome abnormalities or gene mutations.
DSD is common as many as 1 person in 100 to 1 in 1000 people.
Prenatal Screen Detects Fetus Abnormalities during pregnancy
An estimated 240 000 newborns die worldwide within 28 days of birth every year due to birth defects.
The most common severe birth defects are heart defects, neural tube defects and Down
syndrome.
Genetic abnormalities i.e. chromosomal abnormalities (for example Down syndrome or trisomy 21) orsingle gene defects (for rxample SMA, beta thalassemia, Cystic Fibrosis etc.)
Pregnancy after 35
After age 35, there’s ahigher risk of pregnancy-related complications.
The risk of pregnancy loss is higher.
The risk of gestational diabetes increases
The risk of developing high blood pressure during pregnancy is higher.
There’s a greater risk of premature birth and having a baby with a low birth weight.
The risk of chromosomal conditions is higher. Babies born to older mothers have a higher risk of certain chromosomal conditions, such as Down syndrome.
Down syndrome
Occurrence rate: 1 in every 700 births
The most common type of chromosomal abnormality, Down syndrome, also called Trisomy 21, occurs when there is an extra copy of chromosome 21. The extra chromosome can cause physical deformities, developmental defects, and mental retardation.
In order to prevent abnormal birth, the government pays the cost of genetic analysis!
What is a gene?
Genes are small sections of DNA that code for proteins
A genome is an organism’s complete set of genetic instructions (all informations on the DNA). Each genome contains all of the information needed to build that organism and allow it to grow and develop.
gene structure
Human Genome Project, which worked to determinethe sequence of the human genome and identify the genes that it contains, estimated that humans have around 25,000 genes.
In human;
There are 3.2 billion nucleotides in genome
Only %2 of DNA codes GENEs, the rest part is JUNK (noncoding)
Noncoding DNA does not provide instructions for making proteins. Scientists once thought noncoding DNA was “junk,” with no known purpose.
gene structure 2
Each gene has two parts; Promoter and coding region.
A promoter is a region of DNA upstream of a gene where relevant proteins (such as RNA polymerase and transcription factors) bind to initiate transcription of that gene. The resulting transcription produces an RNA molecule (such as mRNA). Promoter regulates whether a gene will be expressed or how much will be expressed.
A coding region is a part of gene which is transcribed as RNA.
From DNA to protein (transcription and translation)
gene expression.
In transcription (RNA synthesis), the information in the DNA of every cell is converted into small, portable RNA messages.
During translation (protein synthesis), these messages travel from the cell nucleus to the ribosomes where they are ‘read’ to make specific proteins.
transcription
Transcription is the process of making an RNA copy of a gene’s DNA sequence.
This copy, called messenger RNA (mRNA), carries the gene’s protein information encoded in DNA.
In eukaryotes, mRNA moves from the cell nucleus to the cell cytoplasm where ribosomes are present
Translation
Translation is the process through which information encoded in messenger RNA (mRNA) directs the addition of amino acids during protein synthesis.
Translation takes place on ribosomes in the cell cytoplasm, where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein.
ALWAYS peptide synthesis start from 5’ of RNA and starts at AUG codon
true
stop codons
UAA
UAG
UGA
How do we have different cell types?
Every cell in the human body shares a common starting point: a fertilized egg. As a result, all of our cells theoretically contain the same DNA.
Although all cells have the same genetic information, each cell type in our body has a different set of active genes.
These different patterns of gene expression cause our various cell types to have different sets of proteins, making each cell type uniquely specialized to do its job.
However, different cells do some common activities (energy production, protein synthesis etc.) which means some genes are expressed in every cells.
How do we regulate gene expression?
Simply, there is regulation
at transcription level (when and how often a gene will be transcribed)
at translation level (which mRNA will be translated and how much will be translated)
on protein activity (when and where a protein will be active)
proteins
as structural material (as inconnective tissueand hair;seecollagen; keratin),
asenzymes andhormones,
as transporters of essential substances such as oxygen (seehemoglobin)
asantibodies,
as regulators of gene expression.
Enzymes need vitamins (coenzyme) or metal atoms (cofactor) for proper function
Proteins may be covalently linked to molecules, as tosugars (glycoproteins), phosphate groups (phosphoproteins), or sulfur (sulfoproteins).
Proteins are not stored for later use in animals. When an animal consumes excess proteins, they are converted intofats(glucose or triglycerides) and used to supply energy or build energy reserves.If an animal is not consuming sufficient protein, the body begins to break down protein-rich tissues, such asmuscles, leading to muscle wasting and eventually death if the deficiency is severe.
true
amino acids
Amino acids are classified as either essential or non-essential
there 20 humans only synthesize half
essential amino acids
Essential amino acids, also known as indispensable amino acids, are amino acids that humans and other vertebrates cannot synthesize from metabolic intermediates. These amino acidsmust be supplied from an exogenous diet because the human body lacks the metabolic pathways required to synthesize these amino acids
non essential amino acids
The non-essential, also known as dispensable amino acids,can be excluded from a diet. The human body can synthesize these amino acids using only the essential amino acids. However, amino acids like arginineand histidine may be considered conditionally essential because the body cannot synthesize them in sufficientquantities during certain physiological periods of growth, including pregnancy, adolescent growth, or recovery from trauma
A protein’s 3D (folding) shape is determined by the interaction between amino acids.
true
Wild-type vs Mutant
Mutation causes amino acid difference in the protein.
The interaction between amino acids are affected.
Protein’s 3D shape changes
mRNA is involved in…
ribosome structure
coding region is only…
2%
transcription is in…
nucleus, mitochondira and chololast
translation occurs in…
cytoplasm and mitochondria because there are ribosomes
presence… defines gender
Y chromosome
gene means
there is a result from that part of the DNA it is RNA if iti s mRNA we synthesize protein
if no product then it is not a gene
true
meaningdul genes…
create functional proteins
gene 2 parts
coding region
promoting region
promoter
decides which gene should be active or expressed
if gene is silenced
no RNA snythesize
if esxpressed
there is RNA synthesize
there are …. genes
250000
we have the same genes why the cells are different?
different cell types = different gene activity= unncessary ones are silent
coding region codes…
RNA
number of RNA changes accoring to protein need no equal amounts
true
some disseases are caused because of high amount of unnecessary protein snytheisze
true
gene expression 2 steps
transcription: RNA snythesize DNA to RNA then RNAs can be recognised by ribosomes, it is inside the nuclues
translation: ribosomes synthesize proteins
each … created a codon
3
RNA types
mRNA: recognised by ribosomes protein snythesis
tRNA: they hold aa they bring aa from the cytoplasm they bind to mRNA when they bind they synthesize protein we need both for protein synthesize
rRNA: component of ribosome
begining of the reading is 5 prime ending is 3 prime
rna and DNA are opposite directions, antiparralel
true
there are … different codons
64
3 of them are end codons
corona virus
RNA to RNA
phophodiester bond btwn
nucleotides
H-H bonds btwn
AT 2
GC 2
23 chromomes in cell nucleus
true
DNA form
not pure relaxed
histone proteins only in eukaryotic
for cell division for mRNA synthesis we need condensed for histone helps that
gene and dna are the same thing
no
after the age of 35
most common down syndrome
genes form proteins…
shape and size of protein define the function
