Unit 2 - Bioethics Flashcards
What is reproduction?
The production of new organisms that resemble the parent organism(s).
What is asexual reproduction?
The production of new organisms that does not involve the fusion of gametes or change in chromosomes.
What is sexual reproduction?
The production of new organisms through the combination of genetic information from two individuals of different sexes.
What is a gamete?
A female of male sex cell (egg/sperm)
What is a zygote?
a cell resulting from the fusion of a male and female gamete (fertilised egg cell)
What is an embryo?
A multicellular organism in the early stage in the development of an offspring - between week 2 and week 8 after fertilisation
What is fertilisation?
The fusion of gametes to produce a zygote
What is mitosis?
A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, used for the production of all cells except sex cells
What is meiosis?
A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, used for the production of gametes
What is a chromosome?
A substance found in the nucleus of a cell which contains a mixture of DNA and protein
What is a diploid?
A cell with two full sets of chromosomes, one set from each parent
What is a haploid?
A cell with 1 set of unpaired chromosomes
What does it mean when a chromosome is condensing and what stage of mitosis does it occur in?
Prophase:
When chromosomes go from threadlike structures itno a more thick and visible state (I to x)
What are the advantages of asexual reproduction?
- Rapid population growth
- Only requires 1 parent
- Quick and easy process to carry out
What are the advantages of sexual reproduction?
- Allows for genetic variation which allows a population to adapt to changes in the environment
What are the advantages of sexual reproduction?
- Allows for genetic variation which allows a population to adapt to changes in the environment
What are some examples of asexual reproduction?
Starfish, strawberries, cactus, hydra, bacteria
What types of cells does mitosis produce?
All cells except gametes
What types of cells does meiosis produce?
Only gametes
What are the five main stages of mitosis?
- Interphase
- Prophase
- Metaphase
- Anaphase
- Telephase
How many cells does mitosis produce? How many chromosomes are in each cell?
2 cells
46 chromosomes
What are the main stages of meiosis?
Meiosis 1:
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telephase
Meiosis 2:
6. Prophase 2
7. Metaphase 2
8. Anaphase 2
9. Telephase 2
How does meiosis create genetically different cells? What stage does this occur in?
Prophase:
When the chromosomes double, they pair up in homologous pairs and “cross over”. When they cross over the exchange genetic information of the same location and purpose, and so the mother chromosome receives information from the father chromosome, and vice versa.
How many cells does meiosis produce? How many chromosomes are in each cell? What kind of division is meiosis?
4
23
Reduction division
What is the function(s) of mitosis?
- Growth and repair of cells
- Development (of an embryo/fetus)
- Asexual reproduction
What is the function(s) of meiosis?
To create genetically different gametes.
What is cytokinesis? Is it a part of mitosis/meiosis?
It is the final division of the cell once the new nuclei have been formed. No, it is not part of mitosis/meiosis.
Name the parts of the male reproductive system and a function of each.
Penis:
- To deliver sperm into the vagina during sex
Testes:
- To produce sperm and testosterone
Seminal vesicle:
- To produce seminal fluid which protects the sperm from the pH of the vagina
Scrotum:
To regulate the temperature of the testicles which are found outside the body.
Urethra:
To carry sperm/semen from the sperm ducts to the penis
Bladder:
To hold urine
Sperm duct:
To deliver sperm from the testes to the urethra
Name the parts of the female reproductive system and a function of each:
Ovaries:
- Contains follicles to release, store and develop eggs
- Production of progesterone and estrogen
Oviducts/fallopian tubes:
- Deliver eggs to the uterus
- Where fertilisation takes place
Uterus:
- Allows for the development of the embryo
- Keep the fetus safe and alive
- Build up the lining of the wall in the case of pregnancy
Cervix:
- Deliver sperm into the oviducts
- Keeps the baby in the uterus until birth
Vagina:
- Deliver sperm into the oviducts
- Way out for fetus during birth
- Kill of any bacteria/foreign substances with acid pH
Urethra/Bladder:
- Storage and release of urine
What is a hormone?
A chemical message secreted by glands that travel through the bloodstream.
What are the four hormones involved in the menstrual cycle? Where is each hormone produced?
FSH (Follicle stimulating hormone) - pituitary gland
LH (Luteinizing hormone) - pituitary gland
Progesterone - corpus luteum
Oestrogen - ovarian follicle
Which hormone has a high level at the beginning of the menstrual cycle and why?
FSH - the decrease of progesterone triggers the start of menstruation. The increase of oestrogen stops the release of FSH.
Which hormone has the highest level during ovulation and why?
LH - oestrogen triggers the release of LH and LH triggers ovulation. Once ovulation has occurred LH levels sink back down due to the release of progesterone from the corpus luteum, which stops the release of LH.
Which hormones has the highest level before ovulation and why?
Oestrogen - when the egg starts to mature oestrogen levels increase and they continue increasing right until ovulation.
What is the function of FSH?
- To stimulate the growth of the ovarian follicle
- Helps the egg mature and prepare it for ovulation
- Triggers release of oestrogen
What is the function of oestrogen?
- To start rebuilding the lining of the uterus
- To trigger the release of LH
- To stop the release of FSH
- Low levels of oestrogen trigger shedding of lining
What is the function of LH?
- Ovulation
What is the function of progesterone?
- To maintain the lining of the uterus
- If the egg is fertilised it will maintain the lining for many months
- If the egg is not fertilised its levels will decrease and trigger the shedding of the lining and the release of FSH
Which hormone has the highest level after ovulation and why?
Progesterone - releases after ovulation from the corpus luteum and stays high until the end of the cycle. Its levels drop if an egg is not fertilised
What are the main events of the menstrual cycle (in order):
Days 1-7:
- Shedding of the uterine lining
- FSH is produced and egg starts to mature
- Oestrogen starts to release
Days 7-13:
- Oestrogen causes the lining to build back up
Day 14:
- Release of LH
- Ovulation
Days 15-28:
- Progesterone is released
- Lining is maintained
- FSH releases again after progesterone decreases
What happens during fertilisation?
A sperm and an egg fuse together an ovidcut.
What happens during pregnancy?
- Placenta and amniotic sac develop
- Zygote develops into embryo
- Embryo develops into fetus
- Fetus develops until week 40
What happens during birth?
- contractions
- water breaks - amniotic fluid passes through
- stronger contractions
- Cervix dilates to 10 mm and labour starts
- Birth - baby passes through the vagina
- Afterbirth - placenta and umbilical cord pass through
