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111 Cards in this Set

  • Front
  • Back
What do chromosomes contain?
Genetic material
DNA (genes) are located where?
on chromosomes
DNA (genes) do what?
control features
When do chromosome pairs seperate?
during meiosis
Definition: Character
feature of organism; may vary (i.e. eye color, height)
Definition: Gene
individual unit of genetic information for specific characters (on specific locations on chromosomes)
Definition: Alleles
alternative versions of gene; why we are not all identical although we may have same genes
How do allels arise?
change in DNA/mutation; those in gametes are inherited
How many alleles can an individual have?
2 but there can be any number in species
Definition: homozygous
have two copies of same allele (AA or aa)
Definition: heterozygous
have two different alleles (Aa)
Definition: phenotype
organism's observable characteristics (eye color, skin color)
Can a phenotype have different alleles?
Definition: genotype
what genes and alleles are present
Definition: dominant allele
phenotype expressed in heterozygote (Aa <-- the capital letter)
Definition: Recessive allele
phenotype that is not expressed in heterozyogot (Aa <-- lower case letter)
Definition: genetic cross
controlled mating to determine inheritance
Definition: P generation, F1 generation, F2 generation
parent of cross, first generation, second generation
Definition: retain idenity
characters can be recovered in F2; all genes are there but only one is dominate over the other
Mendel's Laws
1. units of inheritance behave in certain ways 2. a characters inheritance is predictable 3. the results can be measured
Law of segregation
2 alleles of a gene go into seperage gametes during meiosis. both alleles are passed on and are equally represened in gamates.
Law of independent assortment
how the 2 alleles of one gene go into gametes does not affect how the allels of other genes go into gametes. however if on same chromosome they tend to travel together
Alleles can arise by a _ which occurs where?
mutation; 1. present in parents (majority of the cases and so it is inherited) 2. occurred in making of gametes 3. appeared in new individual
How do we determine how a trait is inherited
a pedigree analysis - which analyzes existing mating
Pedigree analysis
best for simple traits that are controlled by one gene (complete dominance) and not affected by the environment
Definition: autosomal
non-sexed chromosomes
autosomal recessive traits
expressed only if homozygous recessive; may hide in carriers and "skip" generations
autosomal dominant traits
expressed if homozygous dominant or heterozygous dominant; cannot hide
X-linked traits for a male
if expressed in male he has allele (it cant be hidden in a male b/c he only has one x) - SAME for recessive or dominant
x-linked trait for a female
if expressed: she is homozygous recessive; if not expressed she is homoygous dominant or homozygous (a carrier) - SAME for recessive or dominant
x-linked recessive genes are more common in male or female?
male b/c recessive gene can't be masked (males have only one X)
x-linked dominat genes are more common in male or female?
DNA chemical componets
sugar phosate base (nucleotide) + the bases
Describe a DNA structure
double helix, 3D, sugars and phosates form sides, bases pair (A + T, C + G )
Linkage violates which principle?
The principle of independent assortment
The greater the distance b/w genes...
...the higher exchanged frequency b/w them
DNA combines with what to form a chromosome?
a protien
Definition: interphase
cell grows and accumlates materials, new materials and organelles are made, DNA/chromoms duplicate
Definition:Cell division
when a single cell becomes two daugher cells (used for growth/replacement - make more cells - and reproduction - make new individuals -)
Chromosomes at the start of interphase are
single and invisible
Chromosomes at the end of interphase
are doubled and invisible
When are chromosomes are visible?
at the start of cell division
Definition: amino acid
a building block of a protein molecule
Definition: anticodon
the triplet of nucleotides in a tRNA molecule pairs with a specific triplet codon in mRNA during protein synthesis
Definition: catalyst
substance that increases the rate of a reaction w/o being used up in the reaction
Definition: centomere
a specialised part of a chromosome which attaches the chromatids togther during the early stages of cell division
Definition: codominance
two or more alleles making a positive contribution to a phenotype resulting in blending of characters
Definition: codon
atriplet of nucleotide bases in DNA that codes for a specific amino acid in protein synthesis
Definition: continuous variation
a type of variation which shows an even graduation b/w 2 extremes in a population
Definition: crossing over
a process of exchange b/w paired chromosomes which may give rise to new combinations of characters. it takes place by the breaking and rejoiing of chromatids and leads to the formation of chiasmata.
Definition: dihybrid
a hybrid heterozygous at two loci and obtained by crossing homozygous parents with different allels at two give loci (i.e. YYRR + yyrr = YyRr)
Definition: discontinuous variation
a variation in populations where the indiviuals fall within two or more distinct groups with respect to a particular character.
Definition: enzyme
a protien which alters the rate of chemical reactions
Definition: eugenics
theory that the human race could be improved by contolled selective breedingb/w individuals with 'desirable' traits
Definition: genetic code
the means by which ino is carried in the genetic material to control protein synthesis
Definition: genome
the total genes in a basic set of chromosome of an organism
Definition: genotype
the genetic make-up of an organism with regard to a given pair of alleles i.e. a tall pea plant's genotype could be TT or Tt
Definition: haploid
only one set of chromoes (i.e. gametes)
Definition: hybrid
any offspring produced by sexual reproduction b/w 2 visibly different parents
Definition: ligase
an enzyme which cloese breaks in single-stranded DNA (combines them)
Definition: meiosis
cell division in which the chromost # is halved so that the diploid cell gives rise to haploid cells (gametes)
Definition: mRNA
a single-stranded RNA molecule formed by transcription from DNA which carries the info encoded in the gene to the site of protein synthesis on the ribosome
Definition: mitosis
cell division in which daugther cells have the same number of chromosomes as the parent cell
Definition: nucleotide
the basic unity of nucliec acid molecules composed of a phospahte, a sugar, and a base
Definition: phenotype
the outward expression of a gene - the visible chracteristics shown by an organism
Definition: polymerase
an enzyme which catalyses the assembly of nucleotides into RNA or DNA on a DNA template during transcription
Definition: restriction enzyme
an enzyme that makes cuts in double-stranded DNA at specific sites
Definition: ribosome
a strcutre in a cell composed of RNA and proteins, where mRNA is translated and proteins synthesised
Definition: transcription
the process in which messenger RNA is syntheised from a DNA template
Definition: translation
the process by which the information carried in the base sequence of mRNA is used to produce a sequence of amino acis in protein synthesis
Definition: replication
the synthesis of DNA
DNA replication steps
1. two strands unwind and seperate, 2. each strance serves a template for other (new nucleotides base-pair connect, 3. result: 2 identicle double helices (each one part "old" and part "new"
What is the role of enzymes in DNA replication?
they help unwine, separate, start, attach, and connect
Two ways DNA changes
1. errors in copying (permanent in DNA sequence - forms new alleles) 2. damage from radiation + chemicals
What are the roles of proteins in a cell?
they determine phenotype and the structure, movement and protection in the cell
Genes vs Proteins (roles)
Genes control genotype, proteins control phenotype
Genes vs Proteins (informational molecules)
genes: DNA (storage and inheritance) ; proteins: amino acis (activity in cell)
Genes and Proteins
both use order of "letters" for information and languages which need RNA to convert
difference sugar (ribose), single stranced, no thymine but uracil, smaler more moblie and short lived
Transcription occurs where? and does what?
DNA to mRNA --> "rewriting" the information, same language; occurs in nucleus
Translation occurs where? and does what?
mRNA to proteins --> "converting" to a different language; occurs in cytoplasm
Transcription produces
all 3 RNA types and a single stranded RNA
which RNA carries infor for protiens
only mRNA
Each amino acid is coded for by...
at least one codone
true or false: a change in a codon will always change the amino acid
false some codons are used for the same amino acid
Translation steps
1. initation 2. elongation 3. termination
True or false: a change in one amino acid can affect protein funtion
true - a small change can have large effects (i.e. sickle cell anemia)
What is needed for genes to create phenotypes
RNAs, proteins (enzymes), and the environment
Bacteria transfer is hard or easy? why?
DNA can trasfer easily b/w individuals b/c it is made up of simple cells
How can bacteria spread?
it can be picked up from environment, carried by viruses that infect bacteria, or transfrred through connections with other bacteria
What is the consequence of a simple cell bacteria
the resitance to drugs
To take over host cell what much a virus be able to do?
it must be able to replicate genetic material and control protein synthesis
DNA viruses can use host cell's enzymes to...
replicate and be trascribed into mRNA (which will then be translated)
RNA viruses can be translated directly by using enzymes from..
the virus; host cells don't have the enzyme for this
Retroviruses (RNA viruses) are more dangerous b/c
virus provides reverse transcriptase that has no proof-reading ability and high mutation rate
when are chromatids seperated from each other?
mitosis and meisos II
homologous chromosome pair segreate into different daughter cells during
meiosis I -------- key word: DIFFERENT
2 types of nitrogen bases
1. purine (adenine and guanine) 2. pyrimidine (cytosine and thymine and uracil)
basic structure of DNA
a phosphate, a 5-carbon sugar called deoxyribose, and one of four nitrogenous bases, adenine, guanine, cytosine and thymine
When does DNA replicate?
during interphase
what happened when Mendel performed his crosses with plants that were not true-breeding?
when a pruple flowered plant was crossed with a white flowered plant 100% of the plants produced purple flowers
what happened when Mendel let the non true-breeding plants self pollate (F2)
75% of the plants were purple 25% were white
2 types of nitrogen bases
1. purine (adenine and guanine) 2. pyrimidine (cytosine and thymine and uracil)
basic structure of DNA
a phosphate, a 5-carbon sugar called deoxyribose, and one of four nitrogenous bases, adenine, guanine, cytosine and thymine
When does DNA replicate?
during interphase
what happened when Mendel performed his crosses with plants that were not true-breeding?
when a pruple flowered plant was crossed with a white flowered plant 100% of the plants produced purple flowers
what happened when Mendel let the non true-breeding plants self pollate (F2)
75% of the plants were purple 25% were white
a sequence of DNA that contains information for the synthesis of RNA molecules used in the manufacture of proteins is known as
a gene
the process of gene transcription begins with the
bnding of RNA polymerase to a region of DNA called the promoter
a small segment of DNA contains the base sequence CGT. If an mRNA transcript is made that includes this DNA sequence, what will be the anticodon on the tRNA that will bind to the corresponding mRNA codon for this DNA triplet?
To create a protein, which of the following sequences of events must take place?
Transcription of DNA, translation of mRNA, protein formation