Transcript Chromosomes and Cell Reproduction Human Reproduction

Chromosomes and Cell
Reproduction
Human Reproduction
Vocabulary Words…
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75. Cell cycle
Diploid cell
Germ cell
Somatic cell
Daughter cell
Sister chromatid
spindle
Read 116-132,
Gamete
 Homologous
chromosome
 Haploid
 Autosome
Sex chromosome
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1006-1010, 142-143
I. WHY DO CELLS DIVIDE?
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surface area to volume ratio is too small. SA
increases to the S2 and Vol increases to the S3
replace dead cells (wound healing)
growth of organism/development
increase the size of a colony (bacteria)
CAUSES?
environmental stimulation
(cut, available food, injury), genetics, diseases
(cancer)
2,000,000,000,000 (2 trillion) cells are produced
a day (25 million/sec)
II. Reproduction
Reproduction - creation of a new
generation (cell, cells, or multicellular
organism) – a complete DNA set is copied)
 asexual- no egg or sperm cell (i.e.
budding, tuber, cloning, spider plant)
new individual is genetically identical to
the parent.
 Also called a “_______”
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Sexual
reproduction- egg
and sperm unite
 Offspring are
different b/c
chromosomes are
rearranged
 Gametes –
reproductive cells
(sperm and egg)
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III More about chromosomes
X = shorthand for chromosomes
 46 total – 23 from mom and 23 from dad
Chromosomes = DNA + histone proteins
(23 pairs)
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(CHROMATIN)
Double Stranded
(after replication)
centromere
Sister Chromatids
(2)
IV CHROMOSOME NUMBER- how many
of each type of chromosome is present
in a cell
Diploid – A cell or an organism consisting of
two sets of chromosomes: usually, one set
from the mother and another set from the
father.
 Haploid - A set of chromosomes containing
only one member of each chromosome pair.
The sperm and egg are haploid and, in
humans, have 23 chromosomes.
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Chromosome Sets
n = # of unique (haploid)
 2n = # of chromosome pairs (diploid)
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n=4
2n=8
XX
xx
XX
xx
Homologous
Pair
V. CELL Cycle: Interphase, MITOSIS
and cytokinesis
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This is how we grow
and develop from the
very first zygote into
what we are today
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Mitosis –
duplication of the
DNA and splitting
of the nucleus (all
cells except sperm
and egg)
Cell Cycle – life of a eukaryotic cell
Interphase, prophase, metaphase, anaphase,
telephase, cytokinesis (IPMATC)
 Or IMC (interphase, mitosis, cytokinesis)
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Practice
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Calculate the surface area and volume of a
cube with each side equal to 4.5 mm.
Practice
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Calculate the surface area and volume of a
cube with each side equal to 4.5 mm.
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SA= (4.5mm)(4.5mm)(6)=121.5 mm2
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Vol= (4.5mm)(4.5mm)(4.5mm)=91.12 mm3
Practice
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Distinguish between
– Chromosome
– Chromatin
– Chromatid
– Homologous pair
Practice
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Distinguish between
– Chromosome- condensed DNA and histone
– Chromatin- uncoiled DNA and histone
– Chromatid- one strand of a double stranded
chromosome
– Homologous pair- 2 chromosomes that carry
basically the same information
Practice
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Identify each phase of the cell cycle in the
diagram
Practice
Identify each phase of the cell cycle in the
diagram
 Cytokinesis
 Telophase
 Interphase
 Prophase
 Metaphase
 Anaphase
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Practice
What is the diploid
 number of this cell?
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What is the haploid
 number of this cell?
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Where would you
 find each cell type?
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Practice
What is the diploid
 number of this cell? 2n = 6
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What is the haploid
 number of this cell? n= 3
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Where would you
 find each cell type?
 Somatic cell
Germ cell (gamete)
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Interphase
Longest phase of the cell’s life
 Increases in mass
 Increases # of organelles
 Replication of chromosomes
 G1 phase – gap prior to DNA replication
 S phase – DNA replication or synthesis
 G2 – after DNA replicaton
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Mitosis
Nuclear division
followed by
division of the
cytoplasm
(cytokinesis)
 See Lab
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VI Chromosome Number
Each species has a characteristic # of
chromosomes (number is NOT a reflection of
complexity)
 Humans – 23 pairs/46 total
 Dogs (39 pairs/78 total)…Corn (10 pairs 20
total)
 Diploid = pairs of similar chromosomes
 Haploid = one of each type of chromosome
(gametes = egg has 23 and sperm has 23)
 Pairs – homologous pairs (same) = XX
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Types of Chromosomes
Autosomes – do not determine sex (1-22)
 Sex Chromosomes – determine sex and
some other features (X and Y) = 23rd
– XY – male
– XX - female
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Meiosis (only in eggs and sperm)
A type of cell division in which the
chromosome # is reduced by half (46 to
23 haploid)
 Production of gametes (sex cells) – these
cells have half # of chromosomes
 WHY IS THIS SO IMPORTANT?
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Mitosis vs. Meoisis
Hereditary Terms
Fertilization – fusion of gametes –
reconstitutes the proper # of chromosomes
(46)
 Trait – genetic characteristic of an organism
 Gene – DNA sequence that codes for a protein
(may lead to a trait)
 Allele – different forms of a gene
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Practice drawing
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5 homologous pairs of chromosomes
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Metaphase of mitosis
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Metaphase I of meiosis
Homework
Cell Reproduction Cross Word
 Answer the following text questions on the
back
 Pg 134 Q 3-5,7-11,17,18
 Pg 154 3,9,11,19a-g
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stop
Human Reproduction
Read 1006-1010 in book
Male
 Anatomy (parts)
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– Meiosis > in the seminiferous tubules > of the
testes > produces gametes (sperm) at the
rate of millions/day
– Refer to diagram of male reproductive system
Male Physiology (how it works)
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Hormones released by pituitary gland
stimulate sperm production
Sperm matures in the epididymis (they
can swim b/c of many mitochondria)
Sexual arousal causes muscles to
contract and release sperm and fluids
through the penis
Millions of sperm are produced each day
< 20 million = sterility
Male Reproductive System
Female Reproductive System
Anatomy
 Meoisis> in the ovary > produces an ovum
(mature egg) > which is released into the
fallopian tubes > for a journey to the uterus
 Females will have all of their eggs by the time
they are born (different than males)
 A females body prepares for pregnancy each
month…if there is no pregnancy, the female will
menstruate
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Female Physiology
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All gametes are made while the female is a
fetus
Eggs are in prophase I until puberty
Sex hormones stimulate monthly maturation
of eggs to ovum
~28 day cycle (maturation of egg to ovum >
release into uterus (ovulation) with thickening
lining > lining is shed if fertilization does not
occur
Birth control pills disrupt normal hormone
cycle
Fertilization
Occurs in the fallopian tubes as the ovum migrates
 Implantation in the uterine wall
 Placenta and umbilical cord are a combination of baby
and female tissues
 Amniotic sac is for protection (shed cells can be
removed and observed for genetic testing)
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NO BABIES….YET!
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Abstain
Block union of gametes (oral contraception and
condoms)
Chemicals
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RU 486 – nonsurgical abortion – in first 63 days – blocks
pregnancy hormone
Morning after Pills – high dosage of birth control
pills…blocks implantation
Abortion – 1973 Roe vs. Wade – abortions allowed
up to when fetus is viable (24-27 wks) – most
controversial Supreme Court Case to date
Sterilization
1. Cut vas deferens in males – can be reversed
2. Cut fallopian tubes in females – can be reversed
6.
Adoption
Birth Control Pills
Birth control pills use a
combination of HORMONES
to prevent pregnancy…does
not prevent STDS
 Block ovulation
 Delay ovulation
 Block implantation of
embryo (fertilization occurs
though)
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TEST TOPICS
Mitosis/Meiosis, Human Reproduction,
Chromosomes
 Cell Reproduction Lab
 M/M WS, Repro/Devel WS
 Vocab 78-89
 Notes and Text 1006-1010, 142-143, 116132
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