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Reproduction be very cool. Grade 2 science test cheatsheet

Asexual Reprod­uction: Cell Cycle

Cell grows and develops & does normal functions, longest cell cycle phase, late interphase DNA replic­ation occurs
Prophase: Nucleolus disapp­ears, spindle fibres form & attach to centro­meres
Cell divides into 2 daughter cells
Dna molecule unwinds with help of enzyme, bases pair up= 2 geneti­cally id DNA molecs.
Metaphase: Spindle fibres lineup at equator of cell
For both binary and cell cycle
Mitosis: Anaphase: Spindle fibres pull sis. chromatids to opp. poles
Telophase: Nuclear membrane reappears around sis chromatids
Eukaryotic cells use cell cycle

Sexual Reprod­uction Cell Cycle

Meiosis 1
Meiosis 2
Prophase 1: Nucleolus dissolves, Nucleolus dissolves, spindle fibres form, homologous chromo­somes pair, spindle fibres attach to centro­meres, DNA condenses to chromo­somes. Pro 2= same no homo
Metaphase: Spindle fibres push chromo­somes to equator (middle) on 2 sides of equator
same no homo
Anaphase: Homo chromo­somes move to opposite sides of cell (spindle fibres pull)
Sister chromatids separate
Telophase: spindle fibres disappear, nuclear membrane comes back, two nuclei form, after telo cell divides at cleavage furrow, 2 cells
Same, cell later divides after, 4 cells
Still Interphase and Cytoki­nesis. Homologous

Binary Fission

Cell splits to two daughter cells with id DNA
Some bacteria reproduce through binary fission cause they don't have a nucleus
Mutation may occur during dna rep. or when chromo­somes don't move to 2 dtr. cells
Prokar­yotic cells only. Barrier forms between daughter cells as they split

Plant Reprod­uction

male rep. org: stamen
female rep. org: pistil
releases m. gamete
gamete carried to stigma
anther: pollen stored­&p­roduced
Stigma: sticky­&c­aptures male gamete
Pollen grains contain male gamete
style: where the pollen tube is
filament supports anther
ovary: contains ovules
Ovules: surround female gamete
Seed germin­ation=a seed developing to plant

Sexual Reprod­uction

Mating: When sperm & egg meet
Fertil­iza­tion: When gametes fuse to form zygote
Develo­pment: When organism develops into embryo
Embryo: is unborn­/un­hatched offspring in develo­pment process
Fertil­iza­tion: sperm breaks into egg cell and penetrates the cell membrane, then fusses with egg nucleus making zygote
Internal fertil­ization gametes join outside of parents.
External is when gametes join inside parents, embryo inside mom
Embryo is protected
Not protected
More energy
little energy
Produces less
Produces more
More compet­ition for food
Less compet­ition
More likely to survive
Many are not fertilized
Zygote eventually turns into embryo, which eventually makes a complete individual
Morula= End of week 1 (ball of cells) Blastula= End of week 2 (hollow ball of cells, cells can develop into any type of cell) Gastrula= 3 distinct layers of cells (Ectoderm= skin & nerves, Mesoderm= Muscles & bones, Endoderm= lungs, liver, and digestive system lining)
Gamete­s=s­per­m/egg. Sperm cells have flagella & are mobile

Asexual vs Sexual Reprod­uction

Rep. Purpose: Produce a offspring, continue species
Cell Theory: "New cells are formed through the division of existing cells."­
Every species has different method of rep.
Asex. rep.
sex. rep.
Asex. 0->0 0 (parent is now daughter cell)
Sex. 0+0= 0 (Zygote) (parents usually stay alive)
1 Parent
2 parents/ Gametes= sperm, egg
All parent DNA
Offspring geneti­cally different/ Half Dad DNA, Half Mom DNA
Geneti­cally Identical
Genetic diversity= better immunity
Clones are natural, but can also be artificial
DNA is made of many nucleoids liked together
4 types of nucleoids: Adenin­e-T­hym­ine­,Cy­tos­ine­-Gu­anine
DNA coil into condensed form: chromatin
More condensed to chromo­some, when the cell is ready to reproduce
DNA looks like long spiral ladder called double helix
Sides of ladder are made up of sugar & phosphate
If the genetic code messes up it causes genetic mutation.


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