Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

39 Cards in this Set

  • Front
  • Back
one form of a gene
chromosomes the same in both males and females
parts of mRNA that will be translated into protein
study of the distribution of species and processes that resulted in this distribution
nonrandom mating among closely related individuals; leads to homozygous condition, lower fitness
two or more sets of each type of chromosome
base sequences that must be removed before translation
gene flow
physical flow of alleles between populations
-can change the allele frequency in both populations; can also spread new alleles that arise in one population
natural selection
outcome of variations in traits that determine which individuals of a population will survive/reproduce
complete wiping out of a species
the genetic constitution underlying a single trait or set of traits
the physical appearance or functional expression of a trat
initiates transcription (DNA sequence signaling start of gene)
gene pool
collection of all the genes in a population
balanced polymorphism
Occurs when two or more alleles of a trait are maintained
-Population shows this when nonidentical alleles for a trait are maintained at frequencies above 1%
-May emerge when conditions favor heterozygotes
a kind of organism
(transposable elements)
segment of DNA moves from one location to another
genetic drift
random change in allele frequencies over generations; caused by change alone
small scale changes of allele frequencies in a population
State Darwin's Principles of Inheritance
Principle of Dominance
In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation. Offspring that are hybrid for a trait will have only the dominant trait.

Principle of Segregation
During the formation of sex cells each pair of traits is separated so that each sex cell (egg or sperm) carries only one form of each trait

Principle of Independent Assortment
Different pairs of alleles are passed to offspring independently of each other
Know the major chromosomal structure changes
Duplication: gene sequences repeated several times
Inversion: linear stretch within chromosome becomes arranged in reverse direction
Translocation: broken part of chromosome becomes attached to nonhomologous chromosome
Deletion: loss of segment of chromosome
Structure of DNA (Chargaff's rule)
DNA polymerase
attach short stretches of nucleotides to unwound part of templace
DNA ligase
fill in tiny gaps between new short stretches to form continuous strand
Enzymes repair DNA where ???
base-pairing errors have crept into nucleotide sequence
DNA replication occurs only in the ??? direction
5' to 3' (in the direction of the synthesis of the leading strand at the replication fork)
DNA replication can only occur discontinuously in the ??? direction
3' to 5' direction (the lagging strand)
Replication of lagging strand
Short 5' to 3' stretches called Okasaki fragments added one at a time
The nicks in the lagging strand are finally knitted together by DNA ligase
Steps of translation
1. Transcription is initiated by a promoter, a DNA sequence signaling start of gene (TAC)
2. mRNA transcript is released from DNA (new letters)
3. Translation begins. Initiation - the mRNA transcript attached 5' end to ribosome
4. tRNA moves along mRNA for the AUG start codon
5. Elongation - Initiating tRNA positions itself at the first ribosome binding (P)
6. Second tRNA molecule positions itself in the adjacent binding site on the ribosome (A)
7. Peptide bond forms between two amino acids on tRNAs
8. First tRNA breaks off; second tRNA moves into P site
9. Third tRNA positions itself in vacated A site and the process continues
10. Termination - a stop codon in mRNA moves onto ribosome platform
11. Release factors bind to ribosome, triggering detachment of mRNA and the polypeptide chain
Define gene mutation and give examples of agents that cause mutation
Gene mutation - small-scale changes in DNA
-Base-pair substitution: one amino acid replaces another
-Insertion/deletion: base inserted/taken out, resulting in frameshift mutation
-Transposons (transposable elements): segment of DNA moves from one location to another
Central dogma of molecular biology
DNA turns into RNA which turns into protein.
Compare contrast DNA and RNA.
DNA is double stranded, the 5-carbon sugar is deoxyribose, and it has the nitrogenous base thymine.
RNA is single stranded, the 5-carbon sugar is ribose, and uracil replaces thymine.
define genetic equilibrium
This is based on the Hardy-Weinberg theory. The levels of p (the dominant trait) and q (the recessive trait) remain the same over a period of time. The population is not evolving.
bottleneck effect
majority of large population is decimated by catastrophic events and small remaining portion of population often has gene frequency much different than original population
founder effect
new populations are started by a small number of individuals from original population
Distinguish among stabilizing, directional, and disruptive selection processes
Directional selection: allele frequencies shift in consistent direction
Stabilizing selection: intermediate form of trait favored
Disruptive selection: both ends of range of variation are favored/intermediate forms selected against
What occurrences can drive allele frequencies away from genetic equilibrium?
Gene flow
Nonrandom mating
Genetic drift
Define and state possible outcomes of base-pair substitution and base insertion/deletion.
Base-pair substitution: one amino acid replaces another.
Insertion/deletion: base inserted or taken out, resulting in frameshift mutation.

In a base-pair substitution, ACT CGA may become AGT CGA. The G replaced the C. Only that three letter part of the sequence is effected, but it can still cause a mutation.

In an insertion/deletion, ACT GCC TAC could become AGC TGC CTA C if the G was inserted. This throws the whole sequence off and a mutation occurs.
Compare and contrast the gradual model and punctuated equilibrium model for evolutionary change
Punctuated equilibrium model assumes that evolution occurs in spurts, between which there are long periods in which there is little evolutionary change.

The gradualism model assumes that evolution proceeds gradually, with progressive change in a given evolutionary line.