DNA in the Cell Inside the nucleus are chromosomes, which house DNA Chromosome made from proteins +...
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Transcript of DNA in the Cell Inside the nucleus are chromosomes, which house DNA Chromosome made from proteins +...
DNA in the CellDNA in the Cell
Inside the nucleus are chromosomes, which house DNAChromosome made from proteins + histones. Coils DNA so it can fit into a cellEach chromosome consists of identical halves called chromatidsCenter of the chromosome is called the centromere
Number & Types of Number & Types of ChromosomesChromosomes
Sex chromosomes determine the sex of an organismSex chromosomes determine the sex of an organismXX = femaleXX = femaleXY = Male XY = Male All other chromosomes are called autosomesAll other chromosomes are called autosomes
Homologous ChromosomesHomologous ChromosomesEach organism gets two copies of each autosome; 1 from mom and 1 from Each organism gets two copies of each autosome; 1 from mom and 1 from dad (46 total chromosomes; 23 pairs in humans)dad (46 total chromosomes; 23 pairs in humans)
Each 2 paired chromosomes are called homologous chromosomesEach 2 paired chromosomes are called homologous chromosomes
Homologous chromosomes carry genes for the same traitsHomologous chromosomes carry genes for the same traits
Homologous ChromosomesHomologous Chromosomes
How Many Chromosomes?
CARP- 104
ELEPHANT-56
KANGAROO-12
PINEAPPLE-50
SHRIMP-92
ADDER’S TONGUE FERN-1200
Diploid & Haploid CellsDiploid & Haploid Cells
Diploid Cells Diploid Cells Cells with 2 copies of each chromosome Cells with 2 copies of each chromosomeHaploid Cells Haploid Cells Cells with 1 copy of each chromosome Cells with 1 copy of each chromosomeMost cells in the body are diploidMost cells in the body are diploidSex cells (sperm & egg) are haploidSex cells (sperm & egg) are haploid
Diploid & Haploid CellsDiploid & Haploid Cells
Why Do Cells Divide?Why Do Cells Divide?
1.1. Get too big (take in more nutrients than they can metabolize)Get too big (take in more nutrients than they can metabolize)2.2. Death/ Need replacementDeath/ Need replacement3.3. Surface to volume ratio; too much volume, not enough surfaceSurface to volume ratio; too much volume, not enough surface
When do cells divide?When do cells divide?Depends on the type of cell (days, weeks, months, some never divide) Depends on the type of cell (days, weeks, months, some never divide) Cell Cycle Cell Cycle Cells will grow, replicate, and die Cells will grow, replicate, and die
Cell Division in ProkaryotesCell Division in Prokaryotes
Prokaryote Prokaryote unicellular bacteria with no nucleus unicellular bacteria with no nucleus
Binary Fission Binary Fission DNA is replicated, cell doubles in size DNA is replicated, cell doubles in size and splitsand splits
Stages of Cell Cycle in Stages of Cell Cycle in EukaryotesEukaryotes
Interphase Interphase Growth Phase Growth Phase
G1 G1 Cell growth Cell growth
S S Synthesis/ Replication of DNA Synthesis/ Replication of DNA
G2 -> Final growthG2 -> Final growth
Mitosis Mitosis DNA, which has DNA, which has
been replicated (remember last unit?) been replicated (remember last unit?)
needs to be distributed equally needs to be distributed equally
to each new cellto each new cell
Stages of MitosisStages of Mitosis
ProphaseProphase
Chromatin condenses (chromosomes) & nucleus disappearsChromatin condenses (chromosomes) & nucleus disappears
Spindle fibers (microtubules) form & move chromosomesSpindle fibers (microtubules) form & move chromosomes
MetaphaseMetaphase
Spindles align chromosomes in the middle of the cellSpindles align chromosomes in the middle of the cell
AnaphaseAnaphase
Centromeres divide and sister chromatids splitCentromeres divide and sister chromatids split
Chromatids move toward opposite polesChromatids move toward opposite poles
TelophaseTelophase
Chromosomes arrive at opposite ends of cellChromosomes arrive at opposite ends of cell
Nucleus reappearsNucleus reappears
Spindle disappearsSpindle disappears
Cell splits (cytokinesis)Cell splits (cytokinesis)
Stages of MitosisStages of Mitosis
CytokinesisCytokinesis
Animal Cell cleavage furrow pinches one cell into 2 cells
Plant Cell cell plate makes new cell wall; cell splits
Mitosis AnimationMitosis Animation
Additional Mitosis Additional Mitosis VocabularyVocabulary
G0 Phase Cell is neither growing or dividing
Centrioles Create Ropes that pull chromosomes around the cell (make
spindle fibers)
Difference Between Plant Difference Between Plant Cell & Animal Cell MitosisCell & Animal Cell Mitosis
•Plant cells are surrounded by a tough outer case Plant cells are surrounded by a tough outer case called a cell wallcalled a cell wall•Animal cells are surrounded by a soft outer case Animal cells are surrounded by a soft outer case called a cell membranecalled a cell membrane•The first 3 stages of mitosis in plant and animal cells The first 3 stages of mitosis in plant and animal cells are the sameare the same
TelophaseTelophase
Animal Cell Animal Cell Formation of a cleavage furrow Formation of a cleavage furrow
Plant Cell Plant Cell Formation of cell plate Formation of cell plate
Meiosis VocabularyMeiosis Vocabulary
•Diploid Cells cells with 2 of each type of chromosome (1 from mom and 1 from dad)
•n= number of pairs of chromosomes
•Diploid Cells = 2n
•Zygote = fertilized egg
•Gametes= haploid sex cells
•Fertilization= union of egg and sperm
•Sexual Reproduction Parents generate specialized sex cells
MeiosisMeiosis
Getting from diploid to haploid cells: Meiosis
Where does it occur in humans?
Males Testes
Females Ovaries
Meiosis OverviewMeiosis Overview
Meiosis IMeiosis I
Diploid cells splits into 2 haploid cellsDiploid cells splits into 2 haploid cells
Meiosis IIMeiosis II
2 haploid daughter cells undergo mitosis2 haploid daughter cells undergo mitosis
Forms 4 haploid sex cellsForms 4 haploid sex cells
Same as mitosisSame as mitosis
Meiosis IMeiosis I
Prophase IProphase I
Homologous chromosomes pair together (called synapsis)Homologous chromosomes pair together (called synapsis)
Each homologous pair of chromosomes is called a tetradEach homologous pair of chromosomes is called a tetrad
Some chromatids break off and attach to adjacent homologous chromatids Some chromatids break off and attach to adjacent homologous chromatids (crossing over)(crossing over)
Crossing Over creates new genetic combinationsCrossing Over creates new genetic combinations
Metaphase IMetaphase I
Homologous chromosomes line up in the middle of the cellHomologous chromosomes line up in the middle of the cell
Anaphase IAnaphase I
Homologous CHROMOSOMES move to opposite poles of the cellHomologous CHROMOSOMES move to opposite poles of the cell
Random separation of homologous chromosomes is called Independent Random separation of homologous chromosomes is called Independent AssortmentAssortment
Telophase ITelophase I
Chromosomes reach opposite poles of the cellChromosomes reach opposite poles of the cell
Cytokinesis beginsCytokinesis begins
Meiosis IMeiosis I
Meiosis IIMeiosis II
2 haploid cells go through the process of mitosis & cell 2 haploid cells go through the process of mitosis & cell divisiondivision
End result of meiosis II is 4 haploid cellsEnd result of meiosis II is 4 haploid cells
Gamete FormationGamete Formation
In males meiosis creates 4 sperm cells (called In males meiosis creates 4 sperm cells (called spermatids)spermatids)
In females the cytoplasm is unevenly divided so that In females the cytoplasm is unevenly divided so that only 1 big cell is formed, along with 3 other polar only 1 big cell is formed, along with 3 other polar bodiesbodies
Meiosis IIMeiosis II