Section 3a - Flowering plants reproduction Flashcards
What are the petals like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Colourful and large to attract insects
Wind-pollinated plants:
Dull and small
Is there nectar in insect-pollinated plants and/or wind-pollinated plants
Insect-Pollinated plants:
Yes, as a reward for insects
Wind-pollinated plants:
What is the scent like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
sweet smell to attract insects
Wind-pollinated plants:
No smell
What are the stigmas like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Sticky and enclosed within the flower so contact is necessary
Wind-pollinated plants: sticks out of the plant so pollen grains blow off in the wind
What are the anthers like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Enclosed and shielded by the petals so contact is necessary
Wind-pollinated plants:
Hang out of the plant so they can be carried by the wind the pollen grains
What are the pollen grains like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Larger, Sticky
Wind-pollinated plants:
smaller and smoother, so can be carried in the wind
How are seeds dispersed
Wind - seeds are blown and carried by the wind to a new area
water - seed can drop into water (such as a stream and be carried to a new area)
gravity - Seeds can fall down due to gravity
animals - Animals can transport seeds (can carry them or eat and excrete them)
Explain the growth of the pollen tube followed by fertilisation and how it leads to seed and fruit formation
Step one: After pollen has landed on the stigma, it grows a pollen tube down through the style to the ovary.
Step two: The nucleus of the pollen grain travels down the pollen tube and fertilises the nucleus in the ovule.
Step three: The fertilised ovule develops into a seed
complete the sentence:
The ovule forms a _______ and the ovary in which it is found becomes a _________.
The zygote develops into an _________ with small root (_________) and shoot (_________).
The other contents of the ovule develop into a ________ for the young plant when the seed ________.
The ovule wall becomes the ________ or the ________.
The ovary wall becomes the ________; this can take many forms depending on the type of fruit
1) seed
2) fruit
3) embryo
4) radicle
5) plumule
6) food store
7) germinates
8) seed coat
9) testa
10) fruit wall
What conditions are needed for seed germination
Water - to activate enzymes and soften seed coat
Oxygen - for respiration, providing energy for growth
Suitable Temperatures - to activate enzymes
How can seeds be dispersed (5 ways)
Wind: Lightweight seeds with wings or parachutes (e.g., dandelions, sycamore) are carried by the wind.
Water: Seeds float and are dispersed by water (e.g., coconuts).
Animals:
- Internal: Seeds are eaten and excreted by animals (e.g., berries).
- External: Seeds attach to fur or feathers (e.g., burdock).
Explosive: Pods burst and scatter seeds (e.g., peas, gorse).
Gravity: Seeds fall and roll away (e.g., apples, acorns).
Why do seeds disperce
Reduce competition: To avoid competition with the parent plant.
Colonize new areas: To spread and grow in new places.
Increase survival: To escape predators and diseases.
Promote diversity: To adapt to different environments.
Explain the roles of oestrogen and progesterone in the menstrual cycle
Oestrogen:
- Produced by the ovaries.
- Stimulates the growth and repair of the uterus lining after menstruation.
- At high levels, it triggers the release of LH (luteinizing hormone), which causes ovulation (the release of an egg).
Progesterone:
- Produced by the corpus luteum after ovulation.
- Maintains the thickened uterus lining to support a fertilized egg.
- If pregnancy doesn’t occur, progesterone levels drop, causing the lining to break down, leading to menstruation.
Explain the roles of oestrogen and testosterone in developing secondary sexual characteristics
Oestrogen (in females):
- Produced by the ovaries.
- Responsible for the development of female secondary sexual characteristics, such as:
- Breast development.
- Widening of hips.
- Growth of pubic and underarm
hair.
- Start of the menstrual cycle.
Testosterone (in males):
- Produced by the testes.
- Responsible for the development of male secondary sexual characteristics, such as:
- Deepening of the voice.
- Growth of facial, pubic, and
body hair.
- Increased muscle mass.
- Growth of the penis and testes.
What are the roles of oestrogen and progesterone in the menstural cycle
FSH (Follicle-Stimulating Hormone):
- Produced by the pituitary gland.
- Stimulates the maturation of an egg in the ovary inside a structure called a follicle.
- Stimulates the ovaries to produce oestrogen.
LH (Luteinizing Hormone): - Also produced by the pituitary gland.
- Causes ovulation, which is the release of a mature egg from the ovary.
- Stimulates the remaining follicle to form the corpus luteum, which produces progesterone.
How are sperm cells adapted to carry out their function effectively
- Streamlined Shape: Reduces resistance in swimming.
- Flagellum (Tail): Propels the sperm forward.
- Midpiece with Mitochondria: Provides energy for movement.
- Acrosome: Contains enzymes to penetrate the egg.
- Small Size: Enables quick and easy movement through fluids.
How are egg cells adapted to carry out their function effectively
Large Size: Provides space for nutrients to support embryo development.
Nutrient-Rich Cytoplasm: Contains yolk for nourishment after fertilization.
Protective Layer: Zona pellucida prevents multiple sperm from fertilizing the egg.
Meiosis: Produces eggs with half the chromosome number, ensuring genetic diversity.
Receptor Molecules: Facilitate fertilization by binding to sperm.
What is the role of the placenta in the nutrition of the developing embryo
Nutrient Transfer: Moves essential nutrients from the mother’s blood to the embryo.
Gas Exchange: Facilitates oxygen intake and carbon dioxide removal.
Waste Removal: Eliminates waste products from the embryo’s blood to the mother’s circulation.
Hormone Production: Produces hormones that support pregnancy and maintain the uterine environment.
How is the developing embryo protected by the amniotic fluid
Cushioning: Acts as a shock absorber to protect against impacts.
Temperature Regulation: Maintains a stable temperature for development.
Lubrication: Allows movement, preventing the embryo from sticking to tissues.
Infection Protection: Contains antibodies that help guard against infections.
Buoyancy: Supports the embryo, reducing pressure on organs for easier growth.
What are the key stags in sexual reproduction in humans
Gamete Production: Formation of sperm in males (spermatogenesis) and eggs in females (oogenesis) through meiosis.
Fertilization: The sperm and egg unite, usually in the fallopian tube, forming a zygote.
Zygote Development: The zygote undergoes cell division (cleavage) and develops into a blastocyst as it moves to the uterus.
Implantation: The blastocyst implants itself into the uterine lining, establishing a connection with the mother’s blood supply.
Embryonic Development: The embryo develops over several weeks, during which organs and structures form.
Fetal Development: After the embryonic stage, the developing organism is referred to as a fetus, continuing to grow and mature until birth.
Birth: The process of labor and delivery, resulting in the birth of the baby.
Describe the structure and function of the female reproductive system
Ovaries:
- Structure: Almond-shaped organs.
- Function: Produce eggs and hormones (oestrogen and progesterone).
Fallopian Tubes:
- Structure: Tubes extending from the ovaries to the uterus.
- Function: Transport eggs; site of fertilization.
Uterus:
- Structure: Muscular, hollow organ.
- Function: Houses and nourishes the developing embryo.
Cervix:
- Structure: Lower part of the uterus.
- Function: Allows passage of menstrual fluid; opens during childbirth.
Vagina:
- Structure: Muscular canal from the cervix to the external genitalia.
- Function: Receives sperm and serves as the birth canal.
Vulva:
- Structure: External genitalia, including labia and clitoris.
- Function: Protects internal organs and contributes to sexual arousal.
Testes:
- Structure: Oval organs in the scrotum.
- Function: Produce sperm and testosterone.
Seminal Vesicles:
- Structure: Glands near the bladder.
- Function: Produce a nutrient-rich fluid for semen
Urethra:
- Structure: Tube running through the penis.
- Function: Carries urine and semen outside the body.
Penis:
- Structure: External organ used for copulation.
- Function: Delivers sperm to the female reproductive tract.
Scrotum:
- Structure: Pouch of skin that holds the testes.
- Function: Regulates the temperature of the testes for optimal sperm production.
Erectile Tissue
- Structure: Spongy tissue with two corpora cavernosa and one corpus spongiosum.
- Function: Fills with blood to enlarge and stiffen the penis during arousal, helping maintain an erection.
Sperm Duct (Vas Deferens)
- Structure: Muscular tube about 30 cm long.
- Function: Transports mature sperm from the epididymis to the ejaculatory duct during ejaculation.
