Reproduction Flashcards
What are the parts of the male reproductive system?
- Testes
- Scrotum
- Bladder
- Prostate Gland
- Urethra
- Penis
- Sperm ducts
Describe the role of the Testes
They contain microtubules linked togetherthat allow for sperm cells to be formed by a special type of cell division
Describe the role of the Scrotum
Contains the testes and remains at lower temperature
Describe the role of the prostrate gland
Just below the bladder, produces semen and joins sperm duct (vas deferens) to urethra
Describe the role of the Urethra
Carries semen containing sperm out of the body
Describe the role of the penis
Contains erectile muscles and is used to introduce sperm into vagina during ejaculation
Describe the role of the sperm ducts
Transports the sperm from the testes to the urethra
Aka Vas Deferens
What are the parts of the female reproductive system?
- Ovaries
- Oviduct
- Uterus
- Cervix
- Vagina
- Clitoris
Describe the role of the Ovaries
They contain immature eggs. Every month an egg matures and is released
Describe the role of the Oviduct
Carries a mature egg from the ovary to the uterus. Fertilisation occurs here.
Aka Fallopian Tube
Describe the role of the Uterus
Embryo develops here if fertilisation occurs
Describe the role of the Cervix
Ring of muscle at base of uterus keeps growing foetus in place. Sperm must swim through here.
Describe the role of the Vagina
Where sperm are deposited and where the baby will leave during birth
Describe the role of the Clitoris
A lump of tissue at the top of the labia. This becomes full of blood during sexual excitement. The clitoris is very sensitive and is the main source of female sexual pleasure.
How many chromosomes does a normal human cell contain?
23 pairs, 46
What is the meaning of Haploid and Diploid?
Haploid is a cell that only has one set of chromosomes (23 total), while a diploid cell has pairs (46 total)
What is a gamete?
A haploid sex cell, e.g. egg/sperm
Def. Fertilisation
The merging of the gametes to produce a diploid zygote
What is the word for a fertilised egg cell?
Zygote
How does the egg cell move?
The egg cell cannot move on it’s own.
It is wafted out of the oviduct by the ciliated epithelial cells
Def. Ejeculation
The release of semen by the penis
Whatare the adaptations of the sperm cell?
- Haploid nucleus - To carry half of the DNA required for fertilisation
- Flagellum - To move towards the egg, against the current
- Mitochrondria - To provide a large quantity of energy for the flagellum
- Acrosome - Produces digestive fluids to penetrate the egg’s surface
What are the adaptations of the egg cell?
- Haploid nucleus - To carry half of the DNA required for fertilisation
- Cytoplasm - Nutrients are stored to fuel the growth of the zygote once the egg is fertilised
- Zona Pellucida - Layer of egg closes and solidifies after a sperm enters and fertilises the egg
What substances pass from the mother to the foetus through the placenta?
- Oxygen
- Antibodies
- Nutrients e.g. Glucose
- Hormones e.g. HCG, Oestrogen, Progesterone
Which substances pass from the foetus to the mother through the placenta?
Waste Products:
- Carbon Dioxide
- Urea
- Lactic acid
Def. Implantation
In early development, the zygote forms an embryo which is a ball of cells (blastocyst) that implants into the wall of the uterus
What are the steps of development of the egg cell?
- Ovum
- Fertilisation
- Zygote
- Cleavage
- Morula
- Blastocyst
- Implanted Blastocyst
Collectively, steps 4 to 6 are the Embryo
Explain how a substances pass from the mother to the foetus
By active transport and diffusion through the placental membrane
Describe adaptations of the placenta for maximum rate of diffusion
- Lare surface area of the villi
- Placental membrane to separate the blood types and filter the substances that pass through it
- Large intervillous space so tht blood can fully diffuse into the villi
Explain why a pregnant lady should not smoke or drink alcohol
Nicotine, Carbon Monoxide and alcohol are small enough to pass through the placental membrane and cause premature birth, underweight babies and birth defects
Viruses e.g. HIV can also pass through placental membrane
What is the purpose of the Amniotic Sac?
Contains the fluid of the developing foetus, acting as a physical barrier to diseases
What is the purpose of the Amniotic Fluid?
A fluid that absorbs shocks to avoid physical damage to the foetus
What is the purpose of the Placenta?
Exchanges gases, nutrients, waste products, hormones and antibodies between the mother and foetus’ blood.
What is the purpose of the Umbilical Chord?
The veins and arteries of the foetus that deliver nutrients through a conecting tube.
What are the male secondary sexual characteristics?
- Pubic hair
- Development of sexual organs
- Production of sperm
- Body mass increase, including muscle mass
- Voice breaks and deepens
What are the female secondary sexual characteristics?
- Pubic hair
- Development of sexual organs
- Menstruation
- Body mass incease and redistributionto areas such a hips and breast
- Voice deepens slowly
What are the female hormones that regulate the menstrual cycle?
- FSH (Follicle stimulating hormone)
- LH (luteinising hormone)
- Oestrogen
- Progesterone
Where are FSH and LH produced and released from?
The pituitary gland
Where are Oestrogen and Progesterone produced and released from?
The ovaries
Decribe the hormonal control of the menstrual cycle
- The Pituitary gland secretes FSH which causes an egg to mature
- The FSH causes the ovary to secrete oestrogen
- The oestrogen causes the pituitary gland to secrete LH, causing the egg to be released from the ovary
- The empty egg follicle, now a yellow body, secretes pregesterone which, together with oestrogen, mantains the thick lining of the uterus
- If fertilisation does not occur, oestrogen and progesterone levels decrease so the uterus lining breaks down
The cycle repeats
Describe the negative feedback that occurs between the hormones in the menstrual cycle
- FSH is produced, causing the ovary to secrete oestrogen
- The oestrogen reduces the FSH levels and causes LH to be secreted
- The LH causes ann egg to be released, so the follicle, now yellow body, secretes progesterone, which reduces LH and FSH levels
- Oestrogen and Progesterone levels now slowly decrease, so the FSH levels can increase again
What does HIV stand for?
Human Immunodeficiency Virus
What is HIV caused by?
A (retro) virus
How does HIV replicate?
It inserts it’s genetic material, RNA, into it’s host, usualy lymphocyte, tso that when an immune response occurs, this cell replicates the HIV viruses
What cells does HIV target?
Lymphocytes
e.g. T-cells
When does HIV become AIDS?
When their decresed lymphocte numbers result in a reduced ability to produce antibodies
Meaning that the host is in danger - they can’t fight other disease well
What does AIDS stand for?
Aquired ImmunoDeficiency Syndrome
How is the spread of HIV prevented?
- Protection during sexual intercourse e.g. condoms
- Testing people for HIV
- Abstenance (not having sexual intercourse)
- Education
What is the treatment for HIV?
Antiretrovirals
Def. Asexual Reproduction
A process resulting in the production of genetically identical offspring from one parent
What are the advantages of Asexual Reproduction?
- The speed of the process
- The energy efficiency
- It is easier for these organims to exploit the environment
- They can reproduce without having to come into contact with a mate
What are the disadvantages of Asexual Reproduction?
- These species are usually only suited to one habitat and can’t adapt
- They can be wiped out by disease
- These are due to a lack of genetic variation
What are the advantages and disadvantages of Asexual Reproduction in Crops?
Def. Sexual Reproduction
The fusion of the nuclei of the gametes to form a zygote and the production of offspring that are genetically different from each other.
Which parts of the body produce progesterone?
- The Corpus Luteum
- The placenta
Def. Hermaphrodite
Organisms with both male and female organs
What are the parts of the flowering plant?
- Sepal
- Petals
- Stamen
- Carpel
- Ovary
- Stigma
- Filament
- Style
- Micropyle
- Anther
Def. Sepal
Specialised leaves that protect the bud
Def. Petal
Large, colourful membranes that attract pollinators and protect the reproductive organs
Def. Stamen
The male reproductive organs
Def. Carpel
The female reproductive organs
Def. Ovary
In a plant
The organ that contains the ovules
Def. Stigma
The tip of the female organ where pollen attatches
Def. Filament
The long stick holding the anther up so that it can come into contact with pollinators
Def. Style
Stick that holds up the stigma
Def. Anther
The part that produces pollen
Def. Pollination
The way that plants pass on their gametes.
Plants can either be pollinated by wind or by insects (or birds and bats).
Describe the differences between the petals of animal or wind pollination in plants
Large and brightly coloured to shelter reproductive organs and attract insects
Vs
Small and dull, as they are less vital, and not needed to attract insects
Describe the differences between the scent and nectar of animal or wind pollination in plants
Present, powerful scent and nectar to attract insects and have them rub aginst the anthers while trying to obtain nectar
Vs
No scent or nectar at all, as it is no necessary, and it woud be a waste of energy to produce them
Describe the differences between the number of pollen grains produced by animal or wind pollination in plants
A moderate number of pollen graisn is released as the chane of succesful pollination by a pollinator is high
Vs
A large number of pollen grains are produced to increase the changes of pollination occuring, which for one pollen grain are low compared to insect pollinators
Describe the differences between the pollen grains of animal or wind pollination in plants
They are usually large and spiky or sticky to attatch onto an animal in order to be carried away
Vs
Small and light to be easily blown and carried by the wind
Describe the differences between the anthers of animal or wind pollination in plants
They are inside the flower, stiff and firmly attached so they are not damaged by insects entering the flower
Vs
They are outside the flower, and hange on long, flexibe filaments, and release pollen easily
Describe the differences between the stigma of animal or wind pollination in plants
They are inside the flower, and sticky so they pick up pollen grains from pollinators
Vs
They are feathery and hang outside of the flower to catch drifting pollen
Where are the male and female gametes found in plants?
Male gamete in pollen
Female gamete in ovule
Def. Cross Pollination
The transfer of pollen from anther of one plant to the stigma of another plant
What are the advantages of cross pollination compared to self pollination?
- Genetic variation
- Geographic spread
What are the disadvantages of cross pollination compared to self pollination?
- If it is isolated, it will not be able to produce offspring. Multiple plants are needed
- Reliant upon pollinators
- Plant needs to consume energy to make nectar and scent
- Longer growth period
What are the terms for plats with one or two cotyledons?
Plants that form a seed with a single cotyledon are called monocots, while plants with 2 cotyledons are called dicots
Def. Endosperm
Surrounds the embryo and provides nutrition.
Def. Cotyledon
The first leaves produced by plants
Def. Monocot
One seed leaf inside the seed coat
Def. Dicot
Two seed leaves inside the seed coat
What is the life cycle of the flower?
- A new young plant germinates from the seed
- Young plant matures and produces a brightly coloured flower
- Inside the flower, male and female sex cells develop and the male cell is transferred to the female cell
- After the transfer of sex cells, fertilisation occurs in female part of flower
- A seed develops after fertilisation
- The seed is carried away from the parent plant
etc.
How are specialised leaves created in plants?
Hormones are sent from the main plant body to promote the development of specialised leaves
What is the function of the flower?
The only function of the flower is the production of gametes and embryos
Def. Pollinator
Pollinators are animals that carry pollen from the anther of one plant to the stigma of another plant (of the same species)
This enables plants to reproduce.
How does fertilisation occur in plants?
Two nucleus from pollen travels down stigma to ovary through a pollen tube where one fuses with nucleus of ovum
Descrbe in detail what happens to a plant embryo after fertilisation
- Seed contains the zygote which will develop into new plant through division into an embryo
- After germination, embryo grows into seedling
- Surrounding the embryo are structures called cotyledons which contain food
- Some plants have one cotyledon and some have two
- Seeds lay dormant for a period of time, they have little water or activity
- This is an advantage as they can be dispersed to other locations
What are the necessary conditions for germination to occur?
- Water
- Oxygen
- Suitable warm temperature
Why do plants have seeds?
- Transport by unique adaptations sch as hooks, fruit and ways to be carried by the wind
- Dormancy (so seeds awaken at the right humidity, temperature and oxygen levels)
- Protection from external factors so they don’t break easily
What are the characteristics of monocots?
- Parallel veins
- Single cotyledon
- Multples of 3 petals
- Fibrous roots
- Vascular bundles throughout stem
What are the characteristics of dicots?
- Veins branching out
- Two cotyledons
- Multiples of 4 or 5 petals
- Tap roots
- Vascular bundles distributed around the edge of the stem
