RAI — 3A — Reproduction Flashcards
Asexual reproduction?
Reproduction by a single parent to produce genetically identical offspring (clones) via Mitosis
Sexual reproduction
Fertilisation of two sex cells (one gamete from each parent) produced by Meiosis to form a zygote which will develop into non-identical offspring
Fertilisation
Fusion of male and female gametes to form a zygote that undergoes cell division and develops into an embryo
Mitosis
Type of cell division that produces diploid body cells for growth and repair of tissues
Meiosis
Type of cell division that produces haploid cells (gametes)
Zygote
Single cell resulting from fusion of a male and female gamete
Gametes
Reproduction/sex cells (sperm cells, egg cells)
Wind pollenated flower
A flower that distributes pollen via wind
insect pollenated flower
A flower that distributes pollen via insects
Advantages of sexual reproduction?
Increases variation
Offspring can adapt to new environment
Susceptible to diseases due to variation (less harmful to population)
Disadvantages of sexual reproduction
Time-consuming to find mating partner
Not possible for isolated members
Advantages of asexual reproduction
Rapid increase in population
Thrive in suitable environment
Disadvantage of asexual reproduction
Decreases variation
Vulnerable to change in environment due to inadaptability
Less susceptible to diseases due to decreased variation (more harmful to population)
Process of fertilisation?
An Egg Cell and Sperm Cell are haploid gametes, containing 23 chromosomes (half of the 46 chromosomes in a Zygote)
Due to this, reproducing requires the fusion of two haploid gametes via fertilisation to form a diploid Zygote containing 46 chromosomes (half from each parent)
As diploid Zygote carries a mixture of genetic information from both parents, Zygote will undergo Mitosis to develop into an embryo exhibiting genetic variation
Petals in insect pollenated flower
Coloured parts that attract animals to allow pollenation
Anther in insect pollenated flower
Produces pollen that contains male gametes
Filament in insect pollenated flower
Holds the anther
Stigma in insect pollenated flower
Site for pollen to be deposited. Inside the flower to catch pollen when brushed against insect. It is sticky.
Style in insect pollenated flower
Connects the stigma to the ovary
Ovary in insect pollenated flower
Produces the egg (ovules_) and encloses the seeds when they form
Ovules in insect pollenated flower
The name for egg in a plant
Nectary in insect pollenated flower
Produces nectar, a sweet liquid containing sugars as a ‘reward’ for insects
Sepals in insect pollenated flower
Covers the flower in the bud and protects it
Stamen in insect pollenated flower
The male part of the flower, containing an anther attached to a filament
Carpel in insect pollenated flower
The female parts of the flower all together
The male part of the flower is called the ______, consists of the ____ and _____.
The male part of the flower is called the stamen consists of the anther and filament.
The female part of the flower is called the ______ consists of the ______, _____ and _____.
The female part of the flower is called the carpel consists of the stigma, ovary and ovules.
The male gamete is made in the _____ and is found inside the ______ grain. The female gamete is found in the _____ and is called an _____
The male gamete is made in the anthers and is found inside the pollen grain. The female gamete is found in the ovary and is called an ovule
Petals in a wind-pollenated flower
Either have none at all or they are small and dull (Green or Brown coloured) as they do not need to attract insects
Scent and nectar in wind pollenated flower
There is no nectar because they don’t need to attract insects
Number of pollen grains in wind pollenated flower
Large amounts of Pollen to increase chances of pollination
Pollen grains in wind pollenated flower
Smooth and light to be easily carried by wind
Anther in wind pollenated flower
loosely attached to long Filaments outside of Flower to easily release Pollen via wind
Stigma in wind pollenated flower
feathery and outside the Flower to catch drifting Pollen grains
Pollen in insect pollenated flower?
The pollen could be sticky or spiky to attach to the insect.
Advantages and disadvantages of wind pollinated flowers
Adv: Don’t rely on other organisms and there’s less investment of energy
Disadv: No wind = no pollination. No guarantee the pollen will go to the correct plant
Advantages and disadvantages of insect pollinated flowers
Adv: Higher chance of pollination
Disadv: No guarantee that an insect will come. More energy investment. No insects = no pollination
Pollination
The transfer of pollen from the anther to the stigma of a plant
Self-pollination
Transfer of pollen from the anther to the stigma of the SAME plant. ASEXUAL
Cross-pollination
Transfer of pollen from the anther to the stigma of a DIFFERENT plant of the same species. SEXUAL
Insect pollination
Transfer of pollen (by means of sticking to an insect) from the anther to the stigma of a plant
Wind pollination
Transfer of pollen (picked up by wind) from the anther to the stigma of plant
what happens when a pollen grain lands on the stigma?
Pollen tube will grow down the Style until it reaches an Ovule within the Ovary
This allows the Nucleus of Pollen grain to pass along the Pollen tube to fuse with Nucleus of Ovule via fertilisation
As a result, Ovule will form a Seed, while Ovule wall forms the Seed coat, and the rest of Carpel will develop into a Fruit to carry the Seed
Germination?
The sprouting of a seed
Conditions needed for a seed to germinate?
Warm temperature, water, oxygen
Where does a seed get energy required to germinate?
Respiration — glucose (food)
Natural asexual reproduction in plants?
Runners
- plants grow side branches (runners) which have small plantlets at their ends.
- Once the runners touch the soil, the plantlets will grow roots and the new plantlets will grow and become independent from the parent plant
Artificial asexual reproduction in plants?
Cutting
- A section of a healthy parent plant with a new bud is cut off.
- The cutting can either be placed in water until new roots grow or directly placed in soil.
- Sometimes, the stem of the cutting could be dipped into ‘rooting powder’, which contains plant growth regulators (rooting hormones) that encourage new root growth.
- These cuttings are then planted and eventually grow into adult plants that are genetically identical to the original plant
Function of testes?
Two of these produce the male gametes, sperm
Function of scrotum
Sacs of skin that contract and relax to keep the testes cool
Function of seminal vesicles
Adds fluid to the sperm during ejaculation forming the semen
Function of urethra (male)
Carries the sperm or urine (not at the same time) out of the body from the penis
Function of penis
Delivers sperm into the vagina during sexual intercourse
Function of Epidiymus
Stores the sperm
Function of Vas deferens
Tube that carries sperm from the testes, joins to the urethra
function of ovary
Produces female hormones, and stores and releases the ovum
function of oviduct (fallopian tubes)
Two tubes which connect the ovaries to the uterus and carry the egg to the uterus
function of anus
The opening at the end of the digestive tract where bowel contents leave the body
function of muscular uterine wall
protects the growing baby during pregnancy
function of rectum
The last several inches of the large intestine closest to the anus
function of uterus
A hollow, muscular organ that protects and nourishes the fetus
function of vagina
Empty passageway leading from the vaginal opening to the uterus
function of pelvic bone
protect the urinary organs (like the bladder and prostate) as well as the internal sex organs
function of bladder
Muscular sac that stores Urine to expel it from body through Urethra via excretion
function of cervix
Neck or opening to the uterus
function of urethra (female)
Tube that passes Urine out of the body from the Bladder via excretion
function of ovulation
When an egg is released from the ovary and moves down the fallopian tube
function of vulva
The general term for all external female sex organs
How is a sperm cell adapted to its function
Carries genetic information in the nucleus to an egg
Stream lined body allows it to move quickly
Middle piece is packed with mitochondria so it’s able to produce a lot of energy to operate the tail
Tail helps it swim faster
How is an egg cell adapted to its function
Cytoplasm to store food and increases surface area which makes it easier to develop an embryo within it
Ovum has a jelly coating to only allow 1 sperm cell to fertilise the ovum
Menstrual cycle?
Changes that occur within female reproductive system for pregnancy to be viable
Role of progesterone in the menstrual cycle?
thickens blood vessels in the Uterus to maintain the Uterus Lining for Pregnancy
If fertilised Egg cell is implanted in the Uterus lining, Progesterone will ensure Uterus lining is thick and rich in blood vessels to cushion fertilised Egg cell to maintain pregnancy
Role of oestrogen in the menstrual cycle?
Ovaries secrete Oestrogen to stop the secretion of FSH, ensuring only one Egg cell matures in a cycle
Role of the placenta?
Organ which allows substances to diffuse from the mother’s blood to the fetus
Substances such as: Carbon dioxide, urea, oxygen, glucose, minerals, amino acids, fats, antibodies and vitamins
What is the main role of the amnion and amniotic fluid?
Amnio is a membrane that forms around the embryo
The amniotic fluid surrounds the fetus in the amnio and protects and cushions it as it develops. Also prevents pathogens that might get in through the vagina
Secondary sexual characteristics (puberty) in males?
Testosterone (hormone responsible for puberty)
- Growth of Penis and Testes
- Growth of facial and body air
- Muscle development
- Voice breaking
- Sex drive
- Sperm production
Secondary sexual characteristics (puberty) in females?
Oestrogen (hormone responsible for puberty)
- Development of breasts
- Growth of body hair
- Beginning of menstrual cycle
- Sex drive
- Growth of body/pubic hair