Cell & Life Cycles…
1) growth
2) wound repair
3) reproduction
4) cell division
Chromosomes
- contain info
- CONSTRUCT each part of the cell
Eukaryotic nucleus directs…
1) events in the cell
2) whole organisms
3) life cycle
Prokaryotes
-long, circular DNA molecule
Eukaryotes, vary in _____, _____, and _____
numbers, shapes, sizes
Linear DNA is wrapped around…
-histones
= balls of protein
In early stages of nuclear division, chromosomes consist of…
two IDENTICAL sister chromatids held together at CENTROMERE
Sister Chromatids
two identical copies of A chromatid
Centromere
part of chromosome that LINKS sister chromatids
Chromosomal ________ is essential part of cell cycle
duplication
Prokaryotes divide by _______ ______
binary fission
Eukaryotic Cell Cycle
1) interphase
2) m phase
Interphase includes THREE growth phases…
1) G1 Phase
2) S Phase
3) G2 Phase
G1 Phase
-cell parts replicated
S Phase
-DNA is synthesized/replicated
G2 Phase
- cells replicated
- cells prepare to divide
M Phase
-period of cell division
Mitosis
-process of nuclear division
FOUR phases of Mitosis
1) anaphase
2) metaphase
3) prophase
4) telephase
Prophase
- chromosomes condense
- nucleus disappears
- mitotic spindle forms
- chromosomes MIXED up
Late Prophase
- nuclear envelope disappears
- spindle attaches to CHROMOSOMES at centromere
Metaphase
-chromosomes align in MIDDLE of cell
Anaphase
- centromeres DIVIDE
- 2 chromatids are pulled apart by SPINDLE
Telephase
-chromosomes arrive at opposite poles
nuclear envelopes REappear around each set of chromosomes
-spindle dissolves
Cytokinesis
- division of cytoplasm
- differs in plant & animal cells
Animal Cells
- divide from OUTSIDE in
- ring pinches cell, forming trench that splits cell
Plant Cells
- divide from INSIDE out
- central cell plate forms
- splits cell
Life Cycle of eukaryotes: process which…
young individual matures/reproduces
ALL clones produced by ______
mitosis
Some animals reproduce asexually by
budding / regeneration
Many organisms can switch between ______ & ______ reproduction
sexual & asexual
Sexual Reproduction
fusion of gametes (sex cell), produced in specialized structures
Ovaries
- produce eggs
- found in animals & flowering plants
Sperm are produced in the _____ of animals & ______ of flowering plants
testes / anthers
In some species, each individual produces only one kind of gamete, but in
many species, each adult can produce BOTH kinds
Fertilization
- results in single cell Zygote
- hereditary info from both parents unite
Zygote undergoes development…
period of rapid mitosis & cellular specialization
In animals, gametes come from _____ cells
germ
GERM CELLS***
- REPRODUCTIVE cell found in reproductive organ
- becomes GAMETES
SOMATIC CELLS***
- BODY cells
- everything BUT reproductive cells