3a sexual reproduction Flashcards
asexual reproduction (facts, pros, cons)
no of parents: 1
haploid: no
fertilisation: no
genetic: identical
cell division: mitosis
pros: faster, favourable conditions
cons: indentical, smaller gene pool, susceptible to disease
sexual reproduction (facts, pros, cons)
no of parents: 2
haploid: yes
fertilisation: yes
genetic: variation
cell division: miesos for gameres, mitosis for growth
pros: variation, survive, larger gene pool
cons: more energy, slower, finding a mate
haploid vs diploid
haploid = half the number of chromosomes (23)
diploid = full number of chromosomes (46/ 23 pairs)
fertilisation
the fusion of the nuclei of the sperm cell and egg cell
asexual examples
- plants develop underground food storage organs that develop into future parts (TUBERS AND BULBS ) (Natural)
- plants produce side branches w runners and produce plants on them (natural)
- plants, CUTTINGS (artificial), branch cut-off and stems planted, hormones encourage new roots to develop
PENIS
delivers sperm into vagina during sex
TESTES
produce sperm
EPIDIDYMYS
stores sperm
SPERM DUCT/ VAS DEFERNES
tube that carrier sperm into tester
joins uthera
SEMINAL VESICLE
adds fluid to sperm during ejaculation = semen
SCROTUM
sacs of skin that contract/relax to keep testes cool
ERECTILE TISSUE
tissue that hardens during ejaculation and sex
FALLOPIAN TUBES/OVIDUCT
tubes which connect to ovaries to uterus carry egg to uterus
UTERUS
carries fetus
OVARIES
produce female hormones and stores/releases ovum (egg)
VAGINA
leads to uterus
VULVA
external sex organs for female
CERVIX
opening to uterus
SPERM STRUCTURE AND ADAPTATIONS
TAIL: propulsion and swimming
MIDPIECE: mitochondria for swimming
ACROSOME: sac of enzymes to break down ZONA PELLUCIDA to enter egg
EGG STRUCTURE AND ADAPTATIONS
ZONA PELLUCIDE: outer protein layer to regulate amnt of sperm entering
CORTICAL GRANULES: releases enzymes to harden outer layer (so no more sperm enters)
ZP = CELL MEMBRANE
MALE SECONDARY CHARS
TESTOSTERONE
- sperm production
- growth and development of sex organs
- growth of pubic hair
- increase in body mass, growth is muscles
- voice breaks
FEMALE SECONDARY CHARS
OESTROGEN
- menstrual cycle begins, ovulation
- growth and development of sex organs
- growth of pubic hair
- increase in body mass, hips develop
- breasts develop
- voice deepens
MENSTRUAL CYCLE (DAY 0)
- cycle begins
- old egg shed along w uterus lining (endometrium)
MENSTRUAL CYCLE DAY 5
- period stops
- FSH release
- stimulates ovum to mature and develop
MENSTRUAL CYCLE DAY 7
- ovum signals to ovaries, as they develop
- ovaries start to produce oestroegn
- thickens uterus lining
MENSTRUAL CYCLE DAY 14
- ovaries now prod more oestrogen
- brain stop FSH, starts LH
- LH triggers ovulation
- LH TRIGGERS PROGESTERONE RELEASE
- ovum travels down fallopian to uterus
MENSTRUAL CYCLE DAY 20
- ovum reaches uterus
(IF PREGNANT)
- progesterone maintains thickness of utereus lining (endometrium)
empty egg follicle = corpus luteum = secretes prog, provides nutrients and protection
*no pregnancy, production of prog stores, menstruation occurs and cycle restarts (0-28/32 days)
MENSTRUAL CYCLE DAY 28
- end of cycle
- if egg fertilised = stops
- otherwise, will shed from womb
- next egg released from alternate ovary
HORMONE SUMMARY
- FSH
- OESTROGEN
- STOP FSH
- LH
- PROG
- STOP LH
AFTER FERTILISATION..
- FERTILISATION
- zygote
- embryo (16 cells)
- implantation
- foetus after development more
PLACENTA ROLE
- allows substances to diffuse from mothers blodd to fetus
into: o2, glucose, AA, fats, H20, vits & mins, antibodies
out of: urea,CO2
prevents some substances (drugs, alcahhol, pathogens)
BLOOD NEVERRR MIXES
increasing RODO (thin membranes and large sa) = increases rate of GROWTH
AMNION (fluid and sac) ROLE
- cushions and protects fetus from bumps
- prevents pathogens via vaina from getting to fetus
water reaks = amniotic sac breaks
UMBILICAL CORD
connect placenta to embryo
PLANT GAMETES
MALE = POLLEN
FEMALE = OVULE
flower = sex organ of plant
MALE PART OF FLOWER?
STAMEN
= anther + filament
FEMALE PART OF THE FLOWER
CARPEL
= stigma + style + ovary + ovule
ANTHER
produces pollen
FILAMENT
holds anther
PETAL
coloured parts attract animals and insects
SEPAL
covers flower in bud and protects it
PENDUCLE + RECEPTACLE
supports flower, connect to stem
NECTARY
attracts animals and insects
OVARY (Plant)
produces ovules & encloses seeds when they form
STYLE
SITE OF FERTILISATION
(where fertilisation = fusion of nuclei of gametes of ovule and pollen )
connects stigma to ovary
STIGMA
sticky
site for pollen to be deposited
POLLINATION DEFINITION AND 2 TYPES
= transfer of pollen from anther to stigma of a plant
- SELF POLLINATION - within same flower (plant and species)
- CROSS POLLINATION - within diff flowers (diff species)
WIND FLOWER ADAPTATIONS (7)
POSITION OF STAMEN: exposed in wind, pollen easy to blow away
POSITION OF STIGMA: exposed, to catch
TYPE OF STIGMA: feathery, to catch
SIZE OF PETALS: small
COLOUR OF PETALS: no brightly colour (reg. green)
NECTARIES: no
POLLEN GRAINS: smaller, smooth, inflated to carry in wind
INSECT POLLINATED ADAPTATIONS
POSITION OF STAMEN: in flower to insect makes contact (collects pollen)
POSITION OF STIGMA: in flower so insect makes contact (pollination)
TYPE OF STIGMA: sticky to it attaches to insect
SIZE OF PETALS: large to attract
COLOUR OF PETALS: bright to attract
NECTARIES: yes, attract
POLLEN GRAINS: larger, sticky grains/ w hooks, stick to insect body
FERTILISATION PROCESS IN PLANTS
- POLLINATION: pollen lands on stigma, will attatch to specific receptors
- pollen tube grows down style, via release of digestive enzymes
- pollen tube grows towards ovary and enters ovule via micropyle (opening)
- nucleus of pollen passes down tube to fertilise ovule
- fertilised ovule = embryo = seed
ovule = seed, ovary = fruit
PROS OF SEED DISPERSAL
- parent plant = less compitition
- more likely to cross pollinate w parent plant
- genetic variation
CONS OF SEED DISPERSAL
- not easy, invest energy into methods
- unfavourable conditions
METHODS OF SEED DISPERSAL
wind (seeds fly)
animals (eat fruit, egest seed)
water (drops and floats)
explosion (pressure releases seeds and they fly away)
SEED TRANSFORMATION
root = radicle
shoot = plumule
ovule = food store for germination
ovule wall = testa/seed coat
WHAT IS GERMINATION AND WHAT IS NEEDED?
= DEVELOPMENT OF A SEED INTO A PLANT
utilises food reserves bc no ps, as no light
requires:
- OXYGEN
- WATER I
- GLUCOSE FROM STARCH STORES
GROWTH AND PARTS OF A SEED
- (grows first) RADICLE, grows down into soil = roots and absorbs water and mineral ions
- (grows 2nd) PLUMULE, grows upwards towards light = shoot, starts ps
- COTELYDON: food store of carbs and starch, provides nutrients for RADICLE and PLUMULE to grow until ps
- TESTA/SEED COAT: for protection, comes off in the end
