Part 4 - Reproduction Flashcards
Species that reproduce sexually have individuals that differ from each other, whereas asexual reproduction leads to identical individuals within a population. What do you think are the advantages for a species of reproducing sexually in comparison to asexually?
If all individuals in a population are identical they will respond in a similar manner to any external influence. The external influence could be for example lack of food source, how attractive they are to a predator, or susceptibility to a particular catastrophic disease. In any of these three examples the entire population could be wiped out and the species could become extinct. In comparison, species that reproduce sexually will have individuals that differ from each other, which means that the species could respond to external influences differently and have better chances of survival
What is the method of reproduction of a multicellular organism?
Sexual reproduction - two parents to produce offspring
What is the method of reproduction for a single celled organism?
Asexual reproduction
One parent is only needed to produce offspring
Define the term physiology?
How the body works
What is evolution?
It is the concept that life changes over time to enable survival
What are red blood cells otherwise known as?
Erythrocytes
What do erythrocytes do in the body?
Transport oxygen around the body, cells need oxygen to allow chemical processes to occur
What is sickle cell anaemia?
It is a hereditary condition in which blood cells become rigid and crescent shaped.
It is mainly found in African/cartibean/Asian race
What disease does sickle cell anaemia protect against?
Malaria
What symptoms does sickle cell anaemia cause?
Tiredness, pain, lethargy
What is a trophozoite?
A sporozoan in active feeding stage of its life cycle
A parasite during growing/feeding stage
What is a sporozoan?
A parasitic spore forming protozoan
What is a merozoite?
A cell that arises from asexual division of a parent sporozoan during its life cycle
Daughter cells
What is malaria?
It is a serious sometimes fatal disease
The parasites invade red blood cells
What parasite causes malaria?
Plasmodium falciparum
How is malaria spread?
From the anopheles mosquito
Through the saliva
How does malaria invade the body?
The parasites migrate to the liver and multiply
They then enter the blood stream to invade the red blood cells
What are gametes?
It is a special type of cell that each individual involved in sexual reproduction produces
In humans gametes are sperm and egg
Plant - ovules and pollen grain
When gametes fuse together what does this form?
Zygote
From which offspring grows
The only type of cell division that you looked at so far is mitosis. What does mitosis ensure in terms of chromosomes?
It ensures that each progeny cell contains chromosomes that are exact copies of those of the parent cell in every respect
Define the term ‘meiosis’?
A type of cell division in which a cell divides into 4 cells each of which contains half the number of chromosomes of the original cell
How many chromosomes do gametes contain in humans?
Each gamete from both parents contain 23 chromosomes each
There is usually 46 chromosomes in total in a human
What is a zygote?
It is when a male and female gamete fuse together
What sex chromosomes are present in the male?
The sex chromosomes are individually called X and Y
What sex chromosomes are present in a female?
Two X chromosomes
Why are eukaryotes, including humans referred to as being diploid?
Because their chromosomes appear in pairs
What is a haploid cell?
It is a cell that contains half the number of chromosomes as a diploid cell
Gametes are haploid cells
What can sperm also be referred to as?
Spermatozoa
What can eggs in terms of sexual reproduction also be referred to as?
Ova (ovum- singular)
What cells only directly contribute DNA to the next generation?
Haploid cells
Is mitosis a process of asexual reproduction or sexual reproduction?
Asexual reproduction
Is meiosis a process of sexual reproduction or asexual reproduction?
Sexual reproduction
How many stages of meiosis is there?
Two
Meiosis l
Meiosis II
How many phases are there in meiosis 1?
4 Prophase Metaphase Anaphase Telophase (Pmat)
How many phases are there in meiosis II?
4 Prophase Metaphase Anaphase Telophase
What is the process called when multicellular organisms reproduce sexually?
Meiosis
What does meiosis lead to?
The production of new cells called gametes which contain half the genetic material of all other cells in the organism
