BIO Exam 2 Flashcards
Catabolic Pathway
Breaks down sugars into energy
Anabolic Pathway
Creates something from broken down products
Meiosis
Cell division resulting in 4 non-identical haploid cells or gametes
The cell cycle rotates between Meiosis and …
Interphase
Interphase
G1 - cell grows the most
S phase - replication occurs and sister chromatids are formed
G2
Meiosis 1
- Prophase
- Metaphase
- Anaphase
- Telophase
Meiosis: Prophase 1
Sister chromatids and homologous pairs come together to form a tetrad
Crossover Occurs
Meiosis: Metaphase 1
The homologous pairs can line up on the metaphase plate
Independent Assortment Occurs
Independent Assortment
- The ability for homologous pairs to line up on the metaphase plate independently from one another
- Alleles can enter the gametes independently from one another as long as they are on different chromosomes
- causes variation in gametes
Meiosis: Anaphase 1
- The homologous pairs seperate
- The cell now goes from diploid and are now haploid
Meiosis: Telophase 1
Cytokinesis occurs
Meiosis: Prophase 2
The genetic material condenses again and it gets rid of the nuclear envelope
Meiosis: Metaphase 2
The sister chromatids seperate and go towards the poles
Meiosis: Telophase 2
- Cytokinesis occurs
- 4 nonidentical haploid cells are made
Blended Inheritance
- Inheritance occurs from one parent or the other
- Variety would be lost over time
Mendel
Found that you can inherit one trait from both parents
Heterozygote
A zygote with two different alleles of the same gene
Homozygote
A zygote with two identical alleles of the same gene
Phenotype
The physical appearance or expression of trait
Genotype
Letters that represent the traits
Dihybrid Cross - Unlinked
Phenotypic ratio: 9:3:3:1
- Cross of two independent traits
- Occurs due to independent assortment
Dihybrid Cross - Linked
Phenotypic ratio: 3:1
- Cross of two linked traits
- Shows they are not independently assorted
Polyhybrid
- Cross of three or more traits
- Can be solved by multiplication and addition rule only if unlinked
Codominance
When both alleles are dominant both alleles are expressed
- If RR and WW are crossed there will be a 100% probability of RW
- Ex: patchy colored fur
Incomplete Dominance
When you get an intermediate phenotype
- The genotype of the original parents remains discrete and can be expressed in later crosses
- Ex: white flower and red flower create pink flower
Sex-linked Inheritance
Traits that are linked to sex
Human Blood Types
- AA or Ai = A
- BB or Bi = B
AB = AB
ii = O
Epistasis
When one gene is going to affect the expression of another gene
- Phenotypic ratio: 9:3:4
- brown fur gene and a pigment gene
Effect of environment o phenotype
When the environment affects phenotypic expression
- Ex: hydrangea flowers, sickle cell
Pedigree Analysis
The analysis of a family tree to understand the inheritance of genes from parents to offspring
Aneuploidy
Abnormal Chromosome Numbers
How do abnormal chromosome numbers occur?
- The homologous pairs are both pulled to one side or fail to separate in meiosis I
- The sister chromatids fail to separate in meiosis II
- Results in some gametes having more chromosomes and some having too few
Down Syndrom
Caused by the gamete having two extra chromosomes 21
- Results in three chromosomes 21
Patau’s Syndrom
Caused by having extra chromosome 13
Autopolyploid
The cells don’t divide properly
- Results in extra sets of chromosomes
Allopolyploid
Two species with a different number of chromosomes mate and their offspring will have a different number of chromosomes than the parent
- offspring can only mate with others of the same cross, but not with the parent species
Duplication
Added pieces of genetic material
Inversion
Change in order of the nucleotides
Translocation
A piece of genetic material goes onto another chromosome
Deletion
Removal or loss of genetic material
