unit 5: cell cycles (objectives)

identify the two types/forms of DNA

chromatin: uncoiled strands of DNA, could be referred to as "spaghetti"

chromosome: coiled strands of DNA, could be referred to as "sausage"

label structures on a chromosome

composed of two identical chromatids (connected from DNA replication) attached at centromere

know numbers of chromosomes for a variety of organisms (including humans)

unique to each species !

humans, 46

horse, 48

potato, 48

plum, 48

chimpanzee, 48

fern, 1262

identify and explain what a karyotype is

a picture showing the complete set of chromosomes in a cell, arranged by size and shape

list and diagram the parts of the cell cycle

interphase, m-phase, c-phase

identify the processes that occur in each part of the cell cycle

gap 1: cell growth

synthesis: DNA replication/synthesis

gap 2: more cell growth and preparation

mitosis: division of the nucleus

cytokinesis: division of the cytoplasm

list the parts of mitosis

prophase, prometaphase, metaphase, anaphase, telophase

describe the events that occur in each part of mitosis

prophase: the first stage, where chromosomes condense and spindle fibers form

prometaphase: the nuclear envelope breaks down, and spindle fibers attach to chromosomes

metaphase: chromosomes line up along the metaphase plate

anaphase: chromatids are pulled apart to opposite sides of the cell

telophase: chromosomes uncoil, and two new nuclei form

identify the phases on mitosis

interphase: gap 1, synthesis, gap 2

m-phase: mitosis

c-phase: cytokinesis

describe what processes occur during cytokinesis

cleavage furrow guides complete separation, division of cytoplasm

compare and contrast asexual and sexual reproduction and give examples

axsexual: one parent produces identical offspring (binary fission, fragmentation, budding)

sexual: two parents produce genetically varied offspring (spawning - external fertilization, copulation - internal fertilization)

compare and contrast animal cell mitosis and plant cell mitosis

animal cell mitosis:

- centrioles help with mitosis

- cleavage furrow occurs during telophase

- cleavage furrow guides complete separation during cytokinesis

plant cell mitosis:

- no centrioles

- cell plate forms at the equator instead of cleavage furrow

- cell plate indicates where the two new cells are to form their cell walls

know the chromosome number for human somatic cells and sex cells

human somatic cells have 46 chromosomes, sex cells have 23 chromosomes

explain how an organism's sex is determined

determined by the 23rd pair of sex chromosomes:

- females having a pair of XX chromosomes

- males having a pair of XY chromosomes

compare and contrast diploid and haploid and give an example

diploid cells: cells that contain both members of a homologous pair (somatic/body cells)

haploid cells: cells that contain only one member of a homologous pair (germ/sex cells)

explain sexual reproduction and how it contributes to genetic variation

- creates sex cells needed for sexual reproduction

- reduces chromosome number by half so fertilization is successful

- initiates genetic variation

explain genetic recombination and how it relates to evolution

results in genetic variation between parents and offspring, thereby increasing the chance of offspring survival and ultimately species survival

identify and describe the events of meiosis that give rise to variation

crossing over: homologous chromosomes exchange pieces of DNA (occurs in prophase 1)

independent assortment: homologous chromosomes line up at the equator randomly (occurs at metaphase 1 & 2)

identify and explain the parts of meiosis

interphase: cell growth & DNA synthesis

prophase 1 !

- chromatin coils into chromosomes

- nuclear membrane and nucleolus disappear

- spindle fibers and centrioles appear

- homologous chromosomes come together and cross over

metaphase 1 !

- homologous pairs line up along the equator

- independent assortment

anaphase 1 !

- homologous pairs separate

telophase 1 !

- centrioles replicate

prophase 2 !

- chromatin coils into chromosomes

- nuclear membrane and nucleolus disappear

- spindle fibers and centrioles appear

metaphase 2 !

- chromosomes line up at the equator

- independent assortment

anaphase 2 !

- chromatids separate

telophase 2 !

- spindle fibers disappear

- nuclear membrane reappears

cytokinesis: division of cytoplasm

justify the existence of meiosis

fundamental in the passing of genomic information from parent to offspring, while also creating genomic diversity in future generations

compare and contrast mitosis and meiosis

mitosis !

- occurs in all organisms (except viruses)

- creates all body (somatic) cells, like blood cells

- involves one cell division

- produces two diploid daughter cells

- daughter cells are genetically identical

- creates a human cell with 46 chromosomes

meiosis !

- occurs only in plants, animals, and fungi

- creates only sex (germ) cells like sperm cells

- involves two successive cell divisions

- produces 4 haploid daughter cells

- daughter cells are genetically different

- creates a human cell with 23 chromosomes

similarities !

- occurs in plants and animals

- starts with a diploid parent cell

- produces new cells

- cells undergo DNA replication

- same basic steps