Est: Genetics Flashcards
What are genetics?
factors responsible for characteristic traits in organisms.
what is a characteristic trait?
physical or psychological attributes that may vary from one individual to another within the same species.
what is chromatin
a mass of dna and proteins within the nucleus of most cells not undergoing mitosis.
what are chromosomes
structures that are formed when a chromatin contracts before mitosis
what are homologous chromosomes
a paired set of similar chromosomes
in humans 46 chromosomes form…
23 pairs of homologous chromosomes (one from each parent)
what is a karotype
is an ordered representation or an individual’s chromosomes, obtained by grouping them into homologous chromosomes.
what are sex chromosomes
23rd pair of a different sized chromosomes
what is the female sex chromosome
xx
what is the male sex chromosome
xy
what does a dna look like
double helix, twisted ladder shape
what does dna contain
nucleotides
what does each nucleotide contain
-a sugar: deoxyribose
-a phosphate
-one of 4 nitrogenous bases: adenine, thymine, guanine, cytosine
describe the pairing of nitrogenous based
-always pair A with T: A+T T+A
-always pair C with G: C+G G+C
What is a gene?
a segment of DNA containing the instructions to make proteins.
What creates a gene?
a particular sequence of bases (ATGC).
What is a genome?
all of the genes we receive from our parents put together.
What do genes provide?
the information for making proteins which determine our traits
What is a protein?
a molecule that plays a specific role in the functioning of an organism and in the expression of its characteristic traits.
how many proteins exist?
100 000 different proteins exists, each playing a very specific role in the organism
What are proteins composed of?
chains of Amino Acids (21 in all)
What determines the function of the protein?
The sequence of Amino Acids
What is protein made by? Where are they located?
Protein is made by Ribosomes which are located outside the nucleus.
What cannot leave the nucleus?
DNA
Because DNA cannot leave the nucleus, DNA must be…
And this is called the…
copied and carried out to the ribosome to synthesize proteins.
this is called the use of Messenger RNA
(mRNA)
How many strands does DNA have?
double-stranded
How many strands does mRNA have?
single stranded
What replaces Thymine in the mRNA strand?
uracil. T becomes U
What is the sugar that replaces deoxyribose in mRNA strand?
Riboses.
Where des tRNA only exist?
in the cytoplasm outside the nucleus.
What does tRNA carry on both ends?
tRNA carries an amino acid on one end and a nucleotide triplet or codon on the other end.
What is the name of the DNA segments that contain information for making proteins?
Genes
What are the four nitrogenous bases that constitute the nucleotides of DNA? Give the name of each base and the letter used to represent it.
Adenine=A
Thymine=T
Guanine=G
Cytosine=C
State the exact pairing pattern for both all four bases in both DNA and RNA.
DNA=
-A always pairs with T and vice versa.
-C always pairs with G and vice versa.
(4)
RNA=
-A always pairs with U (thymine replaced by uracil)
-T always pairs with A
-C always pairs with G and vice versa.
(4)
In a DNA molecule, which chemical unites make up the rungs of the ladder?
a phosphate group
In a DNA molecule, which two chemical units make up the sides of the ladder?
deoxyribose and nitrogenous bases
What are the four nitrogenous bases in the mRNA strand?
adenine
uracil
cytosine
guanine
What is the sugar molecule in DNA?
deoxyribose
What is the sugar molecule in mRNA?
ribose
write the steps of protein synthesis
- dna is unzipped
- mrna goes into nucleus to copy dna
- leaves nucleus to the cytoplasm
- attaches itself to a ribosome
- ribosome reads codons three at a time
- aug codons start process.
- codons determine which amino acids go to a chain
- aa are brought up to the trna molecules and link to protein chain
- after ribosome sees UAG, UAA, UGA codons, the protein process is completed
- the synthesized protein is released to do its job in the organism.
what are the principles of heredity?
-crossbreeding
-alleles
-genotypes and phenotypes
what is heredity
the transmission of parents character traits to their offspring
what is a pure line
a group of individuals of the same species, which, for a specific character trait, produces only offspring with the same trait, without variation.
what is cross breeding
the exchange of gametes between 2 different individuals during sex
what is a hybrid
an individual obtained by the cross breeding of 2 genetically different individuals
what is generation
a group of individuals descended from common parents
who is gregor mendel
a scientist/priest who was the first to understand how character traits are inherited.
what are alleles
are a possible form of genes. different alleles have different sequences.
what is homozygous
both alleles for the individual are identical
what is heterozygous
the two alleles for the individual are different.
what is dominant
an allele that is expressed when an indictable carries 2 diff alleles for a given gene. (B)
what is recessive
is an allele that is not expressed when an individual carries 2 diff alleles for a given gene (b)
what is a genotype
is an individual’s genetic inheritance. it describes all of an individual’s alleles for specific genes. (non specific)
what is a phenotype
is the way in which a genotype expresses itself. it describes the appearance or state of the individual for one or more character trait. (more specific)
what is cloning
it is asexual reproduction that involves one parent. the offspring is identical to the parent. same dna as parent
when does natural cloning occur
in nature without human intervention
what is budding in natural cloning
a new individual develops from a protrusion that eventually detaches itself from the parent.
what is layering in natural cloning
roots develop from a branch in contact with the ground (branch is on the ground from the stem). detaches itself and becomes a new individual. ex: tomato
what is propagation by cutting in natural cloning
a new individual is formed from a separated section of the plant (other than its seeds)
what is artificial plant cloning
occurs with human intervention. humans take a cutting from a plant and put it in water until it grows roots
describe four steps of animal cloning
- remove the full dna from the cell of an individual to be cloned
- take ovum from another individual and remove nucleus (1/2 of DNA)
- combine full dna to ovum
- implant embryo into the uterus of surrogate mother.
describe reproductive human cloning
application of cloning techniques to get a new individual genetically identical to the one being cloned.
describe therapeutic human cloning
application of cloning techniques to get tissues or organs genetically identical to those of a person in need of transplant or medical grafting
what is molecular cloning
production of multiple copies of the same defective gene to study genetic illnesses like cystic fibrosis
