Bio Chapter 11 Flashcards
Explain the principles Mendel developed
Inheritance-traits genes passed from parents to offspring
Principle of dominance- some alleles are dominant to others and will mask recessive
Segregation of alleles- alleles separate during the formation of gametes so each cell has one
Independent assortment- alleles segragate when looking at more than one trait at a time
(Remember Morgan found it is the chromosomes that have independent assortment not the genes)
describe Mendels experiement and jnow the relating terms (p, f1, f2, cross pollinating, true-breeding)
P generation- true breeding (homozygous) plants that had opposite traits (short vs. Tall) and cross pollinated them.
F1- HYBRIDS one dominant one recessive
f2- offspring were TT Ts or ss
Know the relationship between alleles genes and chromosomes
Genes-sequence of dna that codes for a particular trait
alleles- different forms of genes (T and t)
Chromosomes-contain many genes
Study Putney squares
Yeeeaahhh
Genotype
Genetic make-up
Phenotype
Physical characteristics
Heterozygous
Organisms that have 2 different alleles for a particular trait (hybrids)
Homozygous
Organisms with two identical alleles for a particular trait (true-breeding)to
Dominant
Shows
Recessive
“Disappeared”
Hybrid
Offspring crossed from parents with different traits
Dihybrid
Hybrid x2
Polygenic trait
Traits produced by interactions of several genes
Heredity
the passing on of physical or mental characteristics genetically from one generation to another.
Genetics
Study of heredity
Allele
Different forms of gene
Gene
Sequence of Dna that determines a trait
True-breeding
Create identical offspring
Probability
Likelihood a particular event will occur
Segregation
Alleles separate during the formation of gametes
Independent assortment
Genes for different traits can segregate independently during formation of gametes
Fertilization
Male and female reproductive cells join during sexual reproduction
Multiple alleles
More than two possible alleles exist in a population
Gametes
Sex cells
Hybrids
Offspring crossed from parents with different traits
Red+white=pink
Incomplete dominace
Black+white= spots
Codominance
How many daughter cells does one complete cycle of Meiosis form?
4 haploid cells
What types of cells make gametes during the process of Meiosis?
2N diploid
What’s the difference between a diploid cell and a haploid cell?
Diploid have 2 sets of genes and haploid have 1
What are homologous chromosomes?
Chromosomes that are similar in size,centrome location,and have the same genes on the chromosomes. One from dad one from mom.
What is the process of crossing-over and during which stage of Meiosis does it occur?
Prophase I
Prophase I
Each replicated chromosome pairs with its corresponding homologus chromosome
Metaphase I
Paired homologous chromosomes line up in the middle of the cell
An aphasia I
Spindles pull each homologous pair towards opposite ends of cell
Telephase I/cytokinises
Nuclear membrane forms around each cluster of chromosomes
Cytokinises forms two new cells
Prophase II
Chromosomes become visible
Metaphase, Anaphase, telophase II
Similar to Meiosis I but produces 4 haploid cells
How are cells produced form Meiosis and Mitosis different?
Mitosis are diploid and genetically identical to parent cells, Meiosis are haploid and genetically diverse
What is a tetrad?
2 replicated homologous chromosomes… Looks like 2 X’s
How is speed production different than egg production?
Sperm- all haploid cells are same size and can be used in reproduction
Eggs- 1 haploid cell gets most of the cytoplasm and is the only one used in sexual reproduction
Zygote
Fertilized egg that will grow through Mitosis
Difference between Mitosis and Meiosis
Change in chromosomes number
Number of cell divisions
Mitosis diploid to diploid
Meiosis diploid to haploid
Mitosis 1
Meiosis 2
How can 2 alleles from different genes be inherited together
Genes linkage-basically when they are on the same chromosomes
What were Morgan’s discoveries when studying fruit flies
Gene linkage- modified Mendels principle of individual assortment
How does independent assortment (Mendels principle) relate to Morgan’s discoveries?
Independent assortment does occur but it occurs with chromosomes not individual genes. Morgan studied traits related to chromosomes
What is gene linkage
Some genes seem to always be inherited together (seem to break principles of independent assortment)
What is a gene map? What does it show you?
Gene map- shows relative distances between genes on a chromosome likelihood of 2 genes crossing over which code for certain traits.
