Chapter 11 Flashcards
23 pairs= 46 total (unsomatic cells)
22 pairs = autsomes (have nothing to do with sex but do deal with traits for ex.)
Last pair of chromosomes deals with sex cells — x,y -means boy. x,x means girl
transmission of traits from one generation to nex
Heredity
study of heredity and variation
Genetics
Units of heredity, made up of segments of DNA
Genes
Genes are passed to the next generation by these. These are sex cells.
Gametes
Gametes are also known as what? Somatic cells are also known as what?
Haploids, diploid
Human somatic cells have how many pairs of chromosomes?
23
ordered display of chromosome pairs
Karyotype
union of gametes
Fertilization
fertilized egg
zygote
Gametes are produced by what?
Meiosis
Members of the same chromosome pairs. Are not identical but code for the same information.
Ex–>brown eyes, blue eyes. Info is same with eye color. Just stated a different color and different parent has different trait.
homologous/homologous chromosomes
Like mitosis this is preceded by what?
chromosome replication
Has two “rounds” of division (meiosis 1 and meiosis 2). Nuclear division that creates haploid cells (sex cells)
Meiosis
Before meiosis the nucleus divides and it still must do what?
copy your DNA
The two cell divisions result in how many daughter cells, instead of two daughter cells in mitosis?
4 daughter cells
Each daughter cell in meiosis has only how many chromosomes as the parent cell?
Only has half as many chromosomes as the parent cell
What are the three mechanisms that contribute to genetic variation?
1.) Independent assortment of chromosomes
2.) Crossing over
3.) Random fertilization
Homologous pairs of chromosomes orient randomly at metaphase I of meiosis.
Independent Assortment of Chromosomes
Homologous chromosomes exchange genetic material. Only during prophase I.
Crossing Over
Any sperm can fuse with any ovum (unfertilized egg)
Random Fertilization
Cells in ovary/testes. Is diploid (full set- 23 chromosome pairs)
Interphase
Grows, decides to divide
G1 phase
DNA copies
S phase
cell checks itself
G2 phase
Separate homologous (members of same species)
Meiosis I
nucleus dissolves, spindle fibers form, DNA condenses. Sister chromatids and homologous associate
Prophase I
Sister chromatids and homologous in middle of cell
Metaphase I
homologous are ones who pull apart
Anaphase I
nucleus forms (2); spindle fibers dissolve; decondense (spread back out)
Telophase I
Division of cytoplasm.
Cytokinesis
Made 2 cells. Two cells are not th same/not identical. Not the cells you started with. Not reduced the amount of chromosomes. so.. you have to do it again
Cytokenesis
divide nucleus but goal is to separate the copies/sister chromatids (big blue from big blue)
Meiosis II
Nucleus dissolves, DNA condenses, spindle fibers form, sister chromatids are linked/associate
Prophase II
sister chromatids are in middle of cell
Metaphase II
sister chromatids get pulled apart ( blue and blue split)
Anaphase II
gonna have 4 nucleus reforms (4)
Telophase II
4 cells are made to turn into egg or sperm. 4 haploid cells. not identical
Cytokinesis
Consider an organism whose karyotype shows it to have a total of 60 chromosomes. How many chromosomes would be contained in the sperm of this organism?
A.) 23
B.) 30
C.) 46
D.) 60
E.) 90
B.) 30
_________ separate during anaphase I.
homologous chromsomes
Chromosomes are replicated during the _________ phase.
A.) G1
B.) G2
C.) S
D.) M
E. ) Meta
C.) S
