Chromosomes and Cell Chromosomes and Cell ReproductionReproduction

Human ReproductionHuman Reproduction

Vocabulary Words…Vocabulary Words…

Cell cycleCell cycle Diploid cellDiploid cell Germ cellGerm cell Daughter cellDaughter cell Sister chromatidSister chromatid spindlespindle

GameteGamete Homologous Homologous

chromosomechromosome HaploidHaploid AutosomeAutosome Sex chromosomeSex chromosome

Read 116-132, 1006-1010, 142-1006-1010, 142-143143

ReproductionReproduction Reproduction - creation of a new Reproduction - creation of a new

generation (cell, cells, or multicellular generation (cell, cells, or multicellular organism) – a complete DNA set is organism) – a complete DNA set is copied)copied)

Asexual reproduction- no egg or Asexual reproduction- no egg or sperm cell (i.e. budding, tuber, sperm cell (i.e. budding, tuber, cloning, spider plant)- new individual cloning, spider plant)- new individual is genetically identical to the parent. is genetically identical to the parent.

Also called a “_______” Also called a “_______”

Sexual Sexual reproduction- egg reproduction- egg and sperm (called and sperm (called gametes) unite gametes) unite

Offspring are Offspring are different b/c different b/c chromosomes are chromosomes are a combination a combination from both parentsfrom both parents

IIIIII More about More about chromosomeschromosomes

X = shorthand for chromosomesX = shorthand for chromosomes 46 total – 23 from mom and 23 from 46 total – 23 from mom and 23 from

dad (23 pairs)dad (23 pairs)

Centromere -holds 2 chromatids together

Chromosomes = DNA + histone proteins

Replication turnschromosomes containingone chromatid into chromosomes containing 2 chromatids

Sister Chromatids- Each chromatid is a double helix. (2)

Chromatin = uncoiled DNA

CHROMOSOME NUMBER- how CHROMOSOME NUMBER- how many of each type of chromosome many of each type of chromosome

is present in a cellis present in a cell Diploid – A Diploid – A cell or an or an organism consisting consisting

of two sets of of two sets of chromosomes: usually, one : usually, one set from the mother and another set from set from the mother and another set from the father. All cells in the human body are the father. All cells in the human body are diploid except sex cells.diploid except sex cells.

Haploid - A set of Haploid - A set of chromosomes containing containing only one member of each chromosome only one member of each chromosome pair. The pair. The sperm and and egg are haploid and, are haploid and, in humans, have 23 chromosomes. in humans, have 23 chromosomes.

Chromosome SetsChromosome Sets

n = # of unique chromosomes (haploid)n = # of unique chromosomes (haploid) 2n = # of chromosome pairs (diploid)2n = # of chromosome pairs (diploid)

XXxx XX

xx HomologousPair

n=4 Haploid cell

2n=8 Diploid cell

XX

x

x

Types of ChromosomesTypes of Chromosomes Autosomes – do not determine sex Autosomes – do not determine sex

(1-22(1-22ndnd pair) pair) Sex Chromosomes – determine sex Sex Chromosomes – determine sex

and some other features (X and Y) = and some other features (X and Y) = 2323rdrd pair pair– XY – maleXY – male– XX - femaleXX - female

CELL REPRODUCTION = CELL REPRODUCTION = MITOSISMITOSIS

Mitosis – cell Mitosis – cell reproduction of reproduction of somatic cells (all somatic cells (all cells except sperm cells except sperm and egg) which and egg) which produces genetically produces genetically identical cellsidentical cells– This is how we grow This is how we grow

and develop from the and develop from the very first zygote into very first zygote into what we are todaywhat we are today

Meiosis (only in eggs and Meiosis (only in eggs and sperm)sperm)

A type of cell division in which the A type of cell division in which the chromosome # is reduced by half (46 chromosome # is reduced by half (46 to 23 haploid)to 23 haploid)

Production of gametes (sex cells) – Production of gametes (sex cells) – these cells have half # of these cells have half # of chromosomeschromosomes

WHY IS THIS SO IMPORTANT?WHY IS THIS SO IMPORTANT?

Cell Cycle Interphase is the time

between cell division. This is when the cell grows and replication occurs (DNA is copied). During interphase, DNA is uncoiled (called chromatin).

Mitosis is the division of the cell’s nucleus (chromosomes). Each resulting nucleus has the same number of chromosomes.

Cytokinesis is division of the cell’s cytoplasm.

 

Mitosis or Meiosis

Cytokinesis

 

Interphase

MITOSIS Mitosis results in new cells with genetic material

identical to that of the original cell. This process is the reason for human growth.

Mitosis occurs in all cells of the body except the sex cells (egg and sperm cells). Sex cells undergo a different process called meiosis.

Mitosis has 4 phases: Prophase, Metaphase, Anaphase and Telophase.

PROPHASE

During prophase, the chromsomes supercoil, the nuclear membrane breaks down and the mitotic spindle is formed.

METAPHASE

During metaphase, the chromosomes line up in single file at the center of the cell.

The chromosomes are held in place by the mitotic spindle.

ANAPHASE During anaphase,

the chromatids of each chromosome separate and move slowly toward opposite poles of the cell.

The spindle pulls the chromatids apart.

TELOPHASE The mitotic spindle

breaks down, the chromosomes uncoil, and the nuclear envelope forms around each set of chromosomes.

Differences between mitosis Differences between mitosis and meiosis- Look at lab and meiosis- Look at lab

paperpaper MitosisMitosis

– Metaphase- Metaphase- chromosomes are chromosomes are in single filein single file

– 2 product cells 2 product cells (diploid)(diploid)

– Somatic cellsSomatic cells– 4 phases (PMAT)4 phases (PMAT)

MeiosisMeiosis– Metaphase- Metaphase-

chromosomes are chromosomes are aligned as pairsaligned as pairs

– 4 product cells 4 product cells (haploid)(haploid)

– Sex cells (gamete)Sex cells (gamete)– SynapsisSynapsis– 8 phases (PMAT 1 and 8 phases (PMAT 1 and

2)2)

What if meiosis yields sex What if meiosis yields sex cells with < or >23 cells with < or >23

chromosomes?chromosomes? Down Syndrome Turner Syndrome Klinefelter SyndromeKlinefelter Syndrome

Why does a somatic cell divide?

There is a limit to the size of a cell. The surface area of a cell must be large

enough to meet the volume needs. The larger a cell gets, the smaller the

surface area to volume ratio. When it gets too small, the cell must divide.

Surface area = 6S2

Volume = S3

If each side of a cube is 2cm, what is the surface area and volume of the cube?

What is the cell cycle What is the cell cycle phase? (IPMATC)phase? (IPMATC)

What is the cell cycle What is the cell cycle phase? (IPMATC)phase? (IPMATC)

What is the cell cycle What is the cell cycle phase? (IPMATC)phase? (IPMATC)

What is the cell cycle What is the cell cycle phase? (IPMATC)phase? (IPMATC)

What is the cell cycle What is the cell cycle phase? (IPMATC)phase? (IPMATC)

What is the cell cycle What is the cell cycle phase? (IPMATC)phase? (IPMATC)

Hereditary TermsHereditary Terms

Fertilization – fusion of gametes – Fertilization – fusion of gametes – reconstitutes the proper # of reconstitutes the proper # of chromosomes (46)chromosomes (46)

Trait – genetic characteristic of an Trait – genetic characteristic of an organismorganism

Gene – DNA sequence that codes for a Gene – DNA sequence that codes for a protein (may lead to a trait)protein (may lead to a trait)

Allele – different forms of a gene (brown Allele – different forms of a gene (brown or blue eyes)or blue eyes)

STOPSTOP

Human ReproductionHuman ReproductionRead 1006-1010 in bookRead 1006-1010 in book

MaleMale Anatomy (parts)Anatomy (parts)

– Meiosis > in the seminiferous tubules > Meiosis > in the seminiferous tubules > of the testes > produces gametes of the testes > produces gametes (sperm) at the rate of millions/day(sperm) at the rate of millions/day

– Refer to diagram of male reproductive Refer to diagram of male reproductive systemsystem

Male Physiology (how it Male Physiology (how it works)works)

1.1. Hormones released by pituitary gland Hormones released by pituitary gland stimulate sperm productionstimulate sperm production

2.2. Sperm matures in the epididymis (they Sperm matures in the epididymis (they can swim b/c of many mitochondria)can swim b/c of many mitochondria)

3.3. Sexual arousal causes muscles to Sexual arousal causes muscles to contract and release sperm and fluids contract and release sperm and fluids through the penisthrough the penis

4.4. Millions of sperm are produced each Millions of sperm are produced each dayday

5.5. < 20 million = sterility< 20 million = sterility

Male Reproductive System

Female Reproductive Female Reproductive SystemSystem

AnatomyAnatomy Meoisis> in the ovary > produces an Meoisis> in the ovary > produces an

ovum (mature egg) > which is released ovum (mature egg) > which is released into the fallopian tubes > for a journey to into the fallopian tubes > for a journey to the uterusthe uterus

Females will have all of their eggs by the Females will have all of their eggs by the time they are born (different than males)time they are born (different than males)

A females body prepares for pregnancy A females body prepares for pregnancy each month…if there is no pregnancy, the each month…if there is no pregnancy, the female will menstruatefemale will menstruate

Female PhysiologyFemale Physiology1.1. All gametes are made while the female All gametes are made while the female

is a fetusis a fetus2.2. Eggs are in prophase I until pubertyEggs are in prophase I until puberty3.3. Sex hormones stimulate monthly Sex hormones stimulate monthly

maturation of eggs to ovummaturation of eggs to ovum4.4. ~28 day cycle (maturation of egg to ~28 day cycle (maturation of egg to

ovum > release into uterus (ovulation) ovum > release into uterus (ovulation) with thickening lining > lining is shed if with thickening lining > lining is shed if fertilization does not occurfertilization does not occur

5.5. Birth control pills disrupt normal Birth control pills disrupt normal hormone cyclehormone cycle

FertilizationFertilization Occurs in the fallopian tubes as the ovum Occurs in the fallopian tubes as the ovum

migratesmigrates Implantation in the uterine wallImplantation in the uterine wall Placenta and umbilical cord are a combination of Placenta and umbilical cord are a combination of

baby and female tissuesbaby and female tissues Amniotic sac is for protection (shed cells can be Amniotic sac is for protection (shed cells can be

removed and observed for genetic testing)removed and observed for genetic testing)

NO BABIES….YET!NO BABIES….YET!1.1. AbstainAbstain2.2. Block union of gametes (oral contraception Block union of gametes (oral contraception

and condoms)and condoms)3.3. ChemicalsChemicals

RU 486 – nonsurgical abortion – in first 63 days – RU 486 – nonsurgical abortion – in first 63 days – blocks pregnancy hormoneblocks pregnancy hormone

Morning after Pills – high dosage of birth control Morning after Pills – high dosage of birth control pills…blocks implantationpills…blocks implantation

4.4. Abortion – 1973 Roe vs. Wade – abortions Abortion – 1973 Roe vs. Wade – abortions allowed up to when fetus is viable (24-27 wks) allowed up to when fetus is viable (24-27 wks) – most controversial Supreme Court Case to – most controversial Supreme Court Case to datedate

5.5. SterilizationSterilization1.1. Cut vas deferens in males – can be reversedCut vas deferens in males – can be reversed2.2. Cut fallopian tubes in females – can be reversedCut fallopian tubes in females – can be reversed

6.6. AdoptionAdoption

Birth Control PillsBirth Control Pills

Birth control pills use a Birth control pills use a combination of combination of HORMONES to prevent HORMONES to prevent pregnancy…does not pregnancy…does not prevent STDSprevent STDS

Block ovulationBlock ovulation Delay ovulationDelay ovulation Block implantation of Block implantation of

embryo (fertilization embryo (fertilization occurs though)occurs though)

TEST TOPICSTEST TOPICS

Mitosis/Meiosis, Human Mitosis/Meiosis, Human Reproduction, ChromosomesReproduction, Chromosomes

Cell Reproduction LabCell Reproduction Lab M/M WS, Repro/Devel WSM/M WS, Repro/Devel WS Vocab 78-89Vocab 78-89 Notes and Text 1006-1010, 142-143, Notes and Text 1006-1010, 142-143,

116-132116-132