Biology Flashcards
Three-Dimensional Structure
The protein itself
What does a proteins three-dimensional structure determine
the proteins function
Where do proteins come from?
animal-based foods, its from their DNA
what do genes provide?
Genotype
what do proteins provide?
phenotype
What is a gene?
a segment of DNA that contains instructions for
making at least one protein
what is gene expression
the process of synthesizing a protein from the
information encoded in a gene
what are alleles
Different versions of a gene with such alternative nucleotide “spellings”
Every gene has two parts…
a regulatory sequence and a coding
sequence
Transgenic organisms=
genetically
modified organisms (GMOs)
what is gene therapy?
attempt to replace a person’s defective gene with a healthy one
DNA replication
semi conservative
mRNA
messenger RNA
tRNA
Transfer RNA
rRNA
ribosomal RNA
what is a protein
Protein is a macromolecule
made of repeating amino acid
subunits.
Amino Acids
Building blocks of proteins
Amino Acid Sequence
Amino acids bond together to form a
linear chain.
Where do proteins come from?
A sequence of DNA that
contains the instructions to make
one or more proteins
where are genes found
chromosomes
What is Synthesis of a protein from a
gene called?
Gene expression
Gene expression
the process
of converting information from
the coding sequence of a gene
into protein
Transcription
involves converting DNA to RNA
Translation
involves converting RNA into protein
where does transcription happen?
occurs in the
nucleus of eukaryotic cells
and the cytoplasm of
prokaryotic cells
where does translation happen?
occurs on
ribosomes in cytoplasm
codons
Each codon specifies a
particular amino acid
Universal Genetic Code
Set of rules relating particular
mRNA codons to particular
amino acids
Genetic engineering
manipulating the genome of a living
organism
Organisms that have received recombinant genes are considered what
transgenic or genetically modified organisms (GMOs)
Recombinant gene
a gene that contains parts of different genes that aren’t found together in nature
Gene expression
is controlled in a cell, and this control accounts for its specialization.
Levels of Gene Control
Pretranscriptional control.
Transcriptional control.
Posttranscriptional control.
Translational control.
Posttranslational control.
Pretranscriptional Control
Active genes are found in euchromatin (loosely packed areas of chromatin).
Transcriptional Control.
This control depends on interactions between certain proteins and particular DNA sequences. The proteins are called transcription factors and activators. The DNA sequences are called promoters or enhancers.
Transcription factors
help RNA polymerase bind to a
promoter
Posttranscriptional Control
After transcription, mRNA is processed before leaving the nucleus. Primary mRNA is converted to a mature mRNA
Translational Control
The longer the mRNA is available in the cytoplasm, the more gene product can be translated. Differences in the poly-A tails and/or guanine caps
may determine how long an mRNA is available for translation. Specific hormones may also affect the longevity of mRNA.
Posttranslational Control
Some proteins must be activated after synthesis. Chemical modifications such as phosphorylation may also affect
the activity of a protein. Many proteins function only briefly before they are degraded or destroyed by the cell.
levels of gene control
What are mutations
are permanent changes
in the DNA sequence.
Mutations effects
Effects can range from changing
expression of a gene to complete
inactivity of a protein.
Normal red blood cells are…
round, carry large amounts of
oxygen, and flow well through
blood vessels
sickle cell disease blood cells
differently shaped, do not flow well
through blood vessels.
what is sickle cell disease caused by
a genetic mutation in the beta-globin
gene.
what is Beta-globin?
s a part of
hemoglobin, which carries
oxygen in red blood cells.
The human body contains many cell types that differ in
structure and function
Each cell type contains its own
specific protein combination to distinguish it from other cells.
only certain genes are active in cells that perform specialized functions.
Such as nerve, muscle, gland, and blood cells
Housekeeping genes
govern functions that are common to many types of cells (Active in many cell types for routine functions)
Gene expression is
controlled in a cell, and this control accounts for its specialization
Mutations
are permanent changes in the DNA sequence.
Mutations in the coding sequence of a gene lead to differences in amino acid sequence
These differences can be detrimental, such as in sickled red blood cells.
Point mutations:
substituting one nucleotide for another
Frameshift mutations:
change in the reading frame of a gene
Rearranged DNA mutations:
sections of DNA move
point mutations
frameshift mutations
rearranged DNA mutations
Germ-Line Mutations (hereditary)
These mutations are present in the egg or sperm cells and can be passed from parent to offspring.
Somatic Mutations (nonhereditary)
These mutations are present in non–germ-line cells and cannot be inherited.
Proto-oncogenes
signal cells to progress through the cell cycle at the appropriate time.
Tumor suppressor genes
signal cells to pause STOP the cell cycle to fix mistakes.
Cancer is uncontrolled cell division caused by
mutations in DNA.
Mutations in two types of gene
proto-oncogenes and tumor suppressors, cause most cancers.
Certain alleles are more common in ethnic groups that
have been reproductively isolated for long periods of time
How does the organization of chromosomes, genes, and their alleles contribute to human traits?
Chromosomes are found in the nucleus
How does meiosis produce gametes?
the pairs of chromosomes separate and segregate randomly to produce gametes with one chromosome from each pair
Cancer
disease of unregulated cell division
The cell cycle
is the orderly sequence of stages that occurs between the time a cell divides and the time the resulting daughter cells also divide.
Cells divide to reproduce
themselves for various reasons:
Growth and development, Cell replacement, Heal wounds
Interphase
growth and preparation
Mitosis
separate copies of chromosomes
Cytokinesis
divide into two cells
cell division
the division of the cytoplasm, follows mitosis.
Cytokinesis
Chromosome perspective:
DNA replicates during S phase in interphase.
the division of the nucleus, follows interphase
Mitosis
Sister chromatids
The human body contains many cell types that differ in structure and function
control of gene expression
Only certain genes are active in cells that perform specialized functions.
gene expression
is controlled in a cell, and this control accounts for its specialization.
gene expression
can be used to inactivate a gene without replacing it with another version.
CRISPR
CRISPR ON THE FARM
- genetically modified crops e.g. corn, rice, soya beans…etc.
- genetically modified animals e.g. pig, cattle…
ENGINEERED ECOSYSTEMS
wipe out disease-carrying mosquitoes or ticks
EDITING OUT DISEASE
gene therapy
Cystic Fibrosis
(CF)
what type of disease is Cystic Fibrosis
•Genetic disease
what is cystic fibrosis cause by
a single gene mutation
CFTR gene codes the
transmembrane regulator protein
people with CF have a mutated
version of CFTR that
fails to move ions.
have two copies of every chromosome.
Diploid organisms
are a pair of
chromosomes that contain
the same genes.
Homologous
chromosomes
Alleles
are alternative versions of the same gene that have different
nucleotide sequences.
Zygote
A cell that is capable of developing into an adult organism. The zygote is formed when an egg is fertilized by a sperm
eMbryo
An early stage of development reached when a zygote undergoes cell division to form a multicellular structure
recoMbination
An event in meiosis during which maternal and paternal chromosomes pair and physically exchange DNA segments
inDepenDent assortMent
The principle that alleles of different genes are distributed independently of one another during meiosis.
recessive allele
An allele that reveals itself in the phenotype only if a masking dominant allele is not present.
DoMinant allele
An allele that can mask the presence of a recessive allele.
HeteroZygous
Having two different alleles
HoMoZygous
Having two identical alleles.
punnett square
A diagram used to determine probabilities of offspring having particular genotypes, given the genotypes of the parents.
Where are genes located
on chromosomes, which are physically
transmitted from parent to offspring.
Diploid organisms have
two copies of one organism
homologous chromosomes
One chromosome from each parent is passed to the offspring.
sexual reproduction
A combination of maternal and paternal alleles that join during fertilization
sexual reproduction
Alleles from parents determine genotype and
contribute strongly to phenotype
gametes
reproductive cells that carry only one copy of each chromosome (haploid)
Gametes formed by meiosis
special cell division producing genetically unique haploid cells
Sexual Reproduction
Haploid sperm fertilizes haploid egg –> Result is a diploid zygote –> Zygote divides by mitosis into an embryo
Meiosis occurs only at certain times of the life cycle of sexually reproducing organisms
After the reproductive organs mature to produce gametes.
Mitosis takes place almost continuously in …
all tissues as part of growth and repair
Homologues line up side by side in a
process called
synapsis
