Exam 2 Flashcards
Fertilization
Joining of gametes (sperm and egg)
Gamete
Egg and sperm
Zygote
Single cell of the fused gametes
Haploid
Has half the number of chromosomes (23)
Diploid
Has the normal amount of chromosomes (46)
Binary Fission
Single called organisms that divide into two to make two identical offspring
Genes
Units of inheritance from DNA that encode proteins
Chromatin
DNA and proteins that form a condensed package
Centromere
Holds two sister chromatids together
Sister Chromatids
Two copies of the same chromatin joined together at the centromere
Homologous Pair
23 pairs, one of each pair is taken by one parent
Sex Chromosomes
X and Y chromoses that determine the sex of the offspring
XY- boy
XX- girl
Cytokinesis
Division of cytoplasm splitting of two cells
Interphase
G1- growth to enter S phase
S- synthesis of duplication of DNA
G2- growth to start mitosis or meiosis
Mitosis
Prophase- chromosome becomes visible and nuclear envelope disappears
Metaphase- chromosomes become attached to the spindle fibers
Anaphase- chromosomes move away from one another to opposite poles of the spindle
Telophase- chromatids move to opposite ends of the cell and two nuclei form
Meiosis
Produces four gamete cells for sexual reproduction
Cell plates
In plant cells because of the cell wall. Plants divide their cytoplasm by making a call plate which is composed of membrane and cell wall materials
Crossing over
When homologous chromosomes pair, maternal and paternal chromosomes overlap ends of their sister chromatids and swap genetic information
Character
An inherited feature that varies from one individual to another
Trait
Variations in characters
Allele
Different types of genes
Homozygous
Both alleles from parents are the same
Heterozygous
Both alleles rom parents are different
Dominant
Allele that determines the organisms appearance