Sexual Reproduction Flashcards
What does sexual reproduction involve?
Process of making and fusing together of male and female sex cells.
What are the sex cells called?
Gametes ( egg and sperm )
What does SR requires?
Two parent organisms
Will the offspring be genetically be identical?
The offspring will share genes with the parents,
it will not be genetically identical to either of them.
simple term of sexual reproduction
two different cells combine, and produce an offspring
cell involved are called
Sex cells
Gametes
Female
Male
Egg
Sperm
What is fertilization?
An egg cell and a sperm cell joined together and new cell formed called zygote
What is the new cell formed called?
Zygote
Advances of diverse offspring - animals (1):
diverse offspring:
- Half DNA from mum
- Half DNA from dad
= individual population have slight differences
Advances of diverse offspring - plants (1):
- Resist diseases
- Traits can develop to resist harsh environments and allow organism to survive
Advances of selective breeding for- animals (2)
- Used to develop many types of plants and animals that have desirable traits
Advances of selective breeding for- farming (2)
Agriculture/Farming- better plants, larger animals
Desirable pets
Disadvantages: (4)
- Time & Energy
need to grow and develop old enough to produce sex cells - Search a mate
- Searching = exposure to diseases, harsh environment, predator
- Fertilisation cannot take place during pregnancy ( long as 2 years for some )
Disadvantages quick 4
- Time & Energy
- Mate
- Searching
- Fertilisation NO pregnancy
Advantages quick 4 (3)
- diverse offspring
- selective breeding = desirable traits
- advantages for farming
What is asexual reproduction?
One parent produce offspring without fertilisation
Uniform offspring
Offspring inherit all of their DNA from one parent
GENETICALLY IDENTICAL to each other and parent
Fission: Asexual Reproduction
meaning
& PROCESS
& examples
Cell division in prokaryotes that forms two genetically identical cells
- DNA is copied
- CM pinches inward the middle
- Cell split to form 2 uniform/ identical offspring
eg. Bacteria, Ecoli
Fragmentation of Asexual reproduction
example of producing
- new organism
- new body parts
- Regeneration: offspring grows from a piece of parent
- producing new organisms: sea star.
- body parts: tadpoles, hydra, crabs
Advantages of Asexual Reproduction (4)
- No mate
- No waste energy or time
- Organisms rapidly reproduce
- Uniform offspring
Disadvantages of Asexual Reproduction
- No genetic variation
= less survival in harsh condition
-Dangerous mutation in DNA = off spring has it
How does SR work?
Meiosis
What is Meiosis
process of cell division = 4 cells having half the number of chromosomes as the OG cell
If cell starts with 4 chromosomes meiosis will lead to
2 chromosomes in each four cells
What does the egg produced after meiosis do?
Egg from female combines with sperm from male
Chromosomes from each parents combine to create new offspring
What does the new offspring have?
Full set of chromosomes
Specialised reproductive organ known as?
Gonads
Gonads for female and male?
F: Ovaries
M: Testes
What cells in the gonads rise the gametes ?
Germ cells
Hermaphrodites
A single organism have both egg-producing and sperm-producing organs.
eg earthworm & garden snail
Simultaneous ( synchronous ) hermaphrodism
Both sperm-producing and egg- producing organs are presented in one organisms
Some fish species found in coral reefs change sex.
They are known as..
Sequential hermaphrodites
How many chromosomes does human have?
46 chromosomes
Haploid number
People have 46 chromosomes. Each gametes give 23 chromosomes.
n=23
What is meiosis the process of?
Producing haploid gametes from diploid germ cells
When is chromosomes restored to diploid
When egg is fertilised by a sperm
Meiosis in egg formation produce=
1 eye (ovum) and polar bodies
Meiosis in sperm formation produce=
4 sperms
Nondisjuction
When meiosis goes wrong
similarities of AS and S reproduction?
- method of producing off spring
- pass on genetic info
How many process of division in meiosis?
TWO SETS prophase 1 & 2 metaphase 1 & 2 anaphase 1 & 2 telophase 1 & 2
purpose of meiosis
reduce the number of chromosomes by half and to create genetic diversity.
How is genetic diverse
homologous chromosome pairs line up and exchange pieces-a process called recombination
Recombination increases genetic diversity by putting pieces of slightly different chromosomes together.
What is stem cells?
Unspecialised cells
Two key qualities of stem cells?
- Self Renewal ( They can continuously divide and replicate )
- Potency ; They have the capacity to differentiate into specialised cell types
Two things stem cells can become
- More stem cells
- Specialised cells
How are bone, nerve etc cells produced
Embryonic stem cells and adult somatic stem cell both cultured in a laboratory
Procedure of embryonic stem cells ( 1 of ingredient for other cells )
Stem cells removed from inner cell mass of blastocyst
Procedure of Adult (somatic ) stem cell ( 2 of ingredient for other cells )
Stem cells removed from umbilical-cord blood and bone marrow
What cells are created with the embryonic stem cell and adult (somatic ) cell
Bone cell
Nerve cells
Skin cells
Blood cells
Four types of stem cells ( in order ) of human development
- Totipotent
- Pluripotent
- Multipotent
- Unipotent
Totipotent
Form any cell type
and extra embryonic tissue ( zygote)
Pluripotent
Form any cell type
Embryonic stem cell
Multipotent
Differentiate into a number of closely related cell type
haematopoeitic adult stem cell
Unipotent
CAN NOT DIFFERENTIATE
Capable of self renewal
eg, muscle stem cell
Totipotent examples
Sperm
Morula
Blastocyst
Pluripotent examples
Inner mass cells
Multipotent / Unipotent examples
digestive tissue, nervous tissue, cardiac tissue
Some uses for stem cell therapy
- Skin cells
- Bone Marrow
- Nerve cell
- Retinal cells
Skin cellls: Burn victims
Bone Marrow: Chemo, leuk
Nerve : Parkinsion’s paralysis
Retinal: Blindness
What does stem cell are undifferentiated meaning?
Do not have a specific job or function
Regenerative medicine
Stem cell used to replace damaged bodily tissues
Why do scientists and doctors want to use stem cells?
To help understand how the body works.
See how stem cells develop into tissue to understand the process of how body uses to create new tissues in a controlled and regulated way.
What are three types of a stem cell?
- Embryonic stem cells
- Adult stem cell
Induced- pluripotent stem cell ( IPSCs )
What is the ethical controversy over using human embryonic stem cells for research?
People against embryonic stem cell research argue that using and destroying embryos shows a lack of respect for the value and dignity of life.
Adult stem cells = bette r as there’s consent
How are most embryos obtained?
By using the unused embryos from IVF treatments.
What is the difference between a totipotent stem cell and a pluripotentstem cell?
totipotent = totally powerful
- become any cell
- in iso = become a human
-within four days of fertilisation = cell splits forming tissue of the fetus = no longer totipotent
now plluripotent = increeasingly loss their plasticity
What is the difference between a pluripotentstem cell and a multipotentstem cell?
less plastic == multipotent
- able to become small and limited selection of related cell types
- is able an adult stem cell
What does IPSCs stand for and what are they?
Induced - pluripotent Stem cells
are from specilaised adult somatic cells ( NOT GAMETES ) which are reprogammed to act like pluripotent embryonic stem cells.
Name two potential uses of using IPSCs?
- allow custom tailoring of stem cells therapies to individual patients
- benefit drug testing, thus testing on human tissues made from IPSCS IS GOOD alternative, accurate results = no animal harmed
What is longer embryo stage of development or the foetus stage.
The foetus stage
What is different between MITOSIS and the FIRST division of MEIOSIS?
Homologous chromosomes pair up
In what stage of Meiosis does the DNA become visible?
Prophase I and Prophase II
What carries mature sperm from the epididymis to the urethra for ejaculation?
Vas Deferens
Which organ provides the site for a blastocyst to implant and develop into a foetus?
Uterus
What is it called when a sperm and egg meet?
fertilization
Meiosis is the process to make what kind of cells?
Gametes
The chromosomes that pair up during meiosis, are called __________ chromosomes.
homologous
What causes genetic variation in meiosis?
crossing over of chromosomes
What is one of the advantages, why is it better to reproduce sexually versus asexually?
genetic variation
Chromosomes exchange genetic material during the “crossing over” stage of meiosis, called:
recombination
A human being has a somatic cell that has 46 chromosomes. What is the haploid number found in a gamete?
23
Which part of the flower collects pollen for fertilization?
Stigma
Which part of the flower produces male gametes (pollen)?
Anther
What organ stores and releases ovums (eggs)?
Ovary
These two organs produce sperm in the scrotum.
Testes
What is the correct order of development of a fertilised cell?
zygote, blastocyst, embryo, fetus
Stem cells can come from either embryos OR adult cells.
True
Differences of Asexual Reproduction
- Make genetically identical offspring
- Relatively quick
- One parent
- Less energy
Differences of Sexual Reproduction
- Makes genetically different offspring
- Takes longer
- Two parents
- More energy, more risks
SAME of AS AND S
Method of making offsprings
Pass on genetic information
How many chromosomes does a cell have in a human body ?
46
How many chromosomes in a sex cell?
23
How does baby choromsomes work?
23 chromo from mother
23 chromo from father
= 46 chromo = 2 sets
How many cycles of cell division in meisos?
2 ( Meisos 1 and Meisos 2 )
Stages of both cycles
( Meisos 1 and Meisos 2 )
Prophase 1 and 2
Metaphase 1 and 2
Anaphase 1 and 2
Telophase 1 and 2
Process of meiosis ( before devision ) :
Duplicates its DNA before cell division begins ( prophase )
Each single strand of chromosomes become double stands of chromosomes
Prophase 1
- Chromosomes condense
- Join together in homologous pairs
- Each pair contains one chromo from father and one from mother - different copies of same genes
- Genes are swapped with each pair through process called “crossing over” = helps with genetic variation
Nucleus begins to break down
Metaphase 1
The pairs of chromosomes line up in the middle of the cell
Fibres attach to the chromosomes to two bodies on opposite side of the cells
Anaphase 1
The fibres seperate the pairs by pulling them apart
Telophase 1
Two nuclei form and then the cell splits into two cells = each has 24 double stand of chromo
Meiosis (II)
Each cell will divide again to form FOUR cells with 23 single stranded chromosomes
Prophase (II)
NOW THEY ARE TWO DAUGHTER CELLS, with 23 chromosomes
Chromosomes condenses and nucleus breaks down.
Metaphase (II)
Chromosomes line up in the middle of the cell
Anaphase (II)
Fibres pull single-stranded chromosomes apart
Telophase (II)
Neceuli form and finally cell divides
NOW HAS FOUR SEX CELLS
Info about the FOUR SEX CELLS PRODUCED BY MEISOS
genetically different to EACH OTHER and ORIGINAL cell
What do the four sex cells contain??
Half the original amount of genetic information
What is the four sex cells called
HAPLOIDS
IN MALE these four sex cells are
Sperm cells
IN FEMALE these four sex cells are
One of the cells in an egg cell while the other three are polar bodies
( small cells that do not develop into eggs )
Symbol with haploid and diploid
haploid= n diploid = 2n
What type of cells does mitosis and meiosis happen in
Mitosis : Somatic cells
Meiosis : Sex cells
Chromosomes in meiosis compare to mitosis
Meiosis : chromosomes number remains the same
Mitosis : chromosomes number is halved in each daughter cell
WHY IS STRAWBERRIES CAN BE A SEXUAL REPRODUCTIONS
Insect pollinators visit strawberry flowers. Pollen from one flower joins the egg of another to form seeds that cover the strawberry fruit.
How can trees be both s and as
rely on wind for pollination
new trees also sprout from roots
Which part of the cell determines what traits of the parents are passed to the offspring?
Chromosomes
What needs to happen to chromosomes, before meiosis can begin?
The chromosomes in the parent cell are copied
How does meiosis ensure that a child will have traits from both parents?
The sperm and egg combine to form offspring, each will contribute half the normal amount of chromosomes.
Human body cells have 46 chromosomes, how many sex cells are there?
Two
What does each sex cell contain?
Half the genetic information.
When two human body sex cells join, what happens to the number of chromosomes in the new cell?
At the end of this reduction division, each daughter cell receives only one homologous chromosome from each pair, ending up with one set.
M and M
Is the parent cell haploid or diploid?
Diploid for both
M and M
Are daughter cells haploid or diploid?
Mitosis: Diploid
Meiosis : Hyploid
M and M
In humans, # of chromosomes at the end of division?
Mitosis: 46
Meiosis: 23
M and M
In what type of cells does the division occur?
Mitosis: Body Cell somatic cells
Meiosis: Reproductive cells
gametes
Purpose of crossing over
The crossing over recombines the homologous chromosomes so that the output cells or gametes will carry a different combination of genetic information from the input germ cell.
Define Fertilisation
It is the fusion of gametes to form a new organism of the same species.
Define Gamete
( egg + sperm ) Are haploid = they have a single set of DNA only.
Define Sperm
Male reproductive cell.
Define Ovum
A mature female reproductive cell, which can be divided to give rise to an embryo usually after fertilisation by a male cell.
Define Zygote
Starts dividing, the single cell becomes subdivided into smaller cells.
TWO TYPES OF fertilisation
Internal
External
ADVANTAGES of External fertilisation
Little energy to mate
Large no. offsprings
Offspring spread widely = less competition
ADVANTAGES of INTERNAL fertilisation
- Egg is protected from dehydrated land
- The embryo is isolated within the female = limits predators
- Survival rate is higher
- Enhances fertilisation from males
DISADVANTAGES of External fertilisation
Many gametes go unfertilised
Offspring often do not protect their parents
DISADVANTAGES of INTERNAL fertilisation
Harder to bring both male and female into intimate contract.
Limited amount of offsprings being produced at any given time.
why external fertilisation is far more common in aquatic animals than in terrestrial animals.
sperm need a watery environment to swim to an egg, external fertilisation is limited to animals that either live in aquatic environments or reproduce in a watery environment.
two energy costs of sexual reproduction that are not present in asexual reproduction.
Internal fertilisation = FINDING, ATTRACTING, SECURING FEMALE MATE
External fertilisation = PRODUCING LARGE NO. OF GAMETES IN ORDER TO INCREASE THE CHANGE OF FERTILISATION
r-selected species have:
A high growth rate but low survivability (“cheap” offspring)
K-selected species have:
Low growth rate but high survivability (“expensive” offspring)
features of r-selected
- unstable environment
- little parental care
- early onset maturity
- MANY OFFSPRING
- HIGH MORTALITY
- VARIETY OF OFFSPRING BODY
features of K-selected
- stable environment
- high parental care
- late onset maturity
-LOW OFFSPRING
LOW RATE OF OFFSPRING MORALITY
-OFFSPRING BODY LARGER
LABEL VAGINAL DIAGRAM
PIC ON UR LAPTOP
Role of vagina
Passageway for sperm and menstrual
Role of Cervix
Opening of the uterus
Role of Ovaries
Produce and release female gametes ( egg) and sex hormones like estrogen and progesterone
Role of Fallopian Tube
Site of fertilisation, eggs go to the uterus
Role of Uterus
Supported by various ligaments laterally by the mesometrium.
organ provides the site for a blastocyst to implant and develop into a foetus?
Role of Bladder
Store urine
Role of Protat gland
Produce fluid that go into seman
Role of Penis
Male sex organ, deliver sperm
Role of Utertra
Urine and sperm come out
Role of Vasdeferens
transports mature sperm to the urethra
What carries mature sperm from the epididymis to the urethra for ejaculation?
Role of Testical
Responsible for making sperm and involved in producing a hormone called testosterone
Role of Scrotum
It is a sac of skin that hangs from the body at the front of the pelvis, between the legs. It protects the testicles and major blood vessels, and tubes that release sperms from the testicles.
label male reproductive system
diagram on laptop
What does an epidemiologist do?
Specialise in birth defects, to diagnose patients.
When can birth defects occur
Throughout the course of embryo and foetal development
Birth defects can be a result of:
genetics, lifestyle choices and behaviors, exposure to certain medications and chemicals, infections during pregnancy and a combination of these factors.
What week is the MOST COMMON SITE of birth defects
Week 6, 7, 8 ( the embryonic phrase )
The Thalidomide Story
A drug taken by women, It was later realised that there was a very strong link between the drug and birth defects
(10,000 babies born worldwide with no limbs, only 50% survived)
TAKEN 20TH DAY OF PREGENANCY = CENTRAL BRAIN DAMAGE
21: DAMAGE EYES
22: EARS AND FACE
24: ARMS
28: LEGS
Thalidomide did not damage the foetus if taken after 42 days gestation.
Time period of FIRST TRIMESTER
1 day to 12 weeks FIRST THREE MONTHS
PERIOD OF RAPID GROWTH AND DEVELOPMENT
Time period of SECOND TRIMESTER
16 weeks – 26 weeks
Time period of THIRD TRIMESTER
28 weeks – 40 weeks
By the end of the first trimester
Baby’s organs will be formed and functioning
What happens in the first trimester
2 weeks: The baby, called embryo develops and mestrual period is missed
4 weeks: Beginning of embryo: eyes, ears, nose, spine, digestive tract, and nervous system
tube for future heart starts beating
8 weeks: Baby called fetus, has full organs, heart is functioning, bones begin to function
12 weeks: tooth bud present
fingernails and toe nails forming
baby heart beat might be here
During the second trimester, what CANT HAPPEN
Fetus cannot live outside of the body because its lungs, heart and blood systems have NOT DEVELOPED YET
What happens in the SECOND trimester
month 3 - 6 brain develops a lot
week 16: face starts to look more human, hair, ears stand out, movement might be felt
17 week: eyebrows and eyelashes appear. baby’s skin is shiny, baby’s first stool appear
24 week: sweat gland forms , red and wrinkled skin, early breathing, lungs expand
26 weeks: baby’s outline felt through abdomen, eyes may open
During the third trimester, what HAPPEN
month 6-9.
baby could survive if born before full term, but would need special care
What happens in the THIRD trimester
28 weeks: skin less wrinkled and red. baby can hear and respond
32 weeks: skin is pink, develop taste, aware of sound , pupils react to light
36 weeks: body round and pump
40 weeks : hair is present, testicles of male babies now in the scrotum, baby full term
Embryonic phrase
Fetal growth phrase
week 1 to 8
week 12 to 38
Plant can reproduce sexually
Cones –> contain reproductive structures
What is the male and female cones
Female cones: produces ovules
Male cones: smaller and not visible, produce pollen (visible powder )
When ovules fertilises with pollen =
becomes A SEED
what events occur during prophase 1 in meiosis
crossing over homologous chromosomes
what happens in anaphase ii
seperation of sister chromatids occur
if someone had the same length, centromere position and bandnig pattern when stained, they are called
homologous
skin cancer is caused by
uncontrolled cell division in an area of skin
what happens in metaphase
- Replicated chromosomes attach by centromeres to spindle fibres.
- Replicated chromosomes line up across the equator of the cell.
what happens in Interphase
- Can’t see the chromosomes
2. Nuclear membrane is visible
what happens in Anaphase
- Spindle fibres shorten/retract to opposite ends of the cell.
- Sister chromatids of separate at centromeres.
- Sister chromatids are pulled to opposite ends of the cell.
How many copies of each gene does a human have for:
autosomal
and
X-chromosome
Two: autosomal
Two copies on X chromosome in females, one copy in males.
cystic fibrosis is an autosomal recessive
That two parents who did not have the disease, but produced an offspring that does shows that it must be a recessive disease and the parents were carriers of the allele.
style in a flower
This is the name for the stalk of the pistil.
pistil in flower
The ovule producing part of a flower
filament in flower
The function of the filament is simply to hold up the anther, extending it up to an accessible part of the flower for pollinators reach, or for the wind to disperse the pollen.
petal in flower
Petals are modified leaves that surround the reproductive parts of flowers.
male part in flower
stamen which has anther and filament
female part in flower
top to bottom
pistil which has stigma, style, ovary, ovule
ways of pollination
Strategies and adaptations for pollination (insect, wind, water)
two stages for prenatal development
embryonic stage and fetal stage
when does fetal and embryonic take place
fetal: week 12 to 38
embryonic: fertilisation of egg to week 8 of development
Abnormal development causes of birth defects
heart defects.
cleft lip/palate.
Down syndrome.
spina bifida.
