Reproduction Flashcards
what is asexual reproduction?
only involves one parent, organisms are genetically identical to each other and their parent, rely on mutations for variations in DNA.
Where is DNA stored?
the cell’s nucleus contains DNA. DNA is wound up tighly into chromosomes. Chromosomes contain many genes.
What is a gene?
a length of dna is the ‘instruction’ how to make a protein - also called a gene
what is a diploid cell?
Diploid is a cell or organism that has paired chromosomes, one from each parent.
what is a haploid cell?
(sex cells)
1 copy of each chromosome,
gametes (reproductive cells) are haploid
what is sexual reproduction?
production of new living organisms involving two parents,
what are gametes?
an organisms reproductive cells, they are made by meiosis
what is mitosis?
a process where a single cell divides into two identical daughter cells (cell division)
what is meiosis?
form of cell division which produces four non-identical, haploid sex cells or gametes
advantages of sexual reproduction
produces variation in offspring, disease is less likely to effect entire population, species can easily adapt to new enviroments.
advantages of asexual reproduction
only one parent is needed, population can increase rapidly
disadvantages of sexual reproduction
time and energy are needed to find a mate, not possible for to reproduce individally, slower
disadvantages of asexual reproduction
does not lead to variation, disease may effecy entire population, cannot adapt easily to changes in enviroment.
What is sexual reproduction?
Sexual reproduction involves the fusion of two gametes (egg and sperm) from two parents, resulting in offspring with genetic variation.
What is asexual reproduction?
Asexual reproduction involves only one parent, and offspring are genetically identical to the parent.
Give an example of an organism that reproduces sexually.
Humans, animals, and most plants reproduce sexually.
Give an example of an organism that reproduces asexually.
Bacteria and some plants (e.g., strawberries) reproduce asexually.
What is a bacterial growth curve
A bacterial growth curve is a graph that shows how the number of bacteria in a population changes over time.
Name the four phases of the bacterial growth curve.
The four phases are lag phase, log phase, stationary phase, and death phase.
What happens in the lag phase of bacterial growth?
In the lag phase, bacteria are adjusting to their environment and not dividin
What happens in the log (exponential) phase of bacterial growth?
In the log phase, bacteria are dividing at a rapid rate, leading to exponential growth.
What is binary fission?
Binary fission is the process by which bacteria and some other organisms reproduce asexually, where one cell divides into two identical daughter cells.
What happens to the DNA during binary fission?
The DNA is replicated, and then the cell splits into two, with each new cell receiving a copy of the DNA.
Is binary fission a form of sexual or asexual reproduction?
Binary fission is a form of asexual reproduction.
What are chromosomes?
Chromosomes are structures made of DNA and proteins that carry genetic information. They are found in the nucleus of eukaryotic cells.
How many chromosomes do humans have?
Humans have 46 chromosomes (23 pairs).
What is the difference between a chromosome and a chromatid?
A chromosome consists of two chromatids connected by a centromere. Chromatids are identical copies of a chromosome formed during DNA replication.
What does diploid mean?
Diploid cells have two sets of chromosomes (one set from each parent). Humans have diploid cells for most of their body cells (46 chromosomes).
What does haploid mean?
Haploid cells have one set of chromosomes. Gametes (sperm and egg cells) are haploid, with 23 chromosomes in humans.
Why is it important for gametes to be haploid?
Gametes need to be haploid so that when fertilization occurs, the resulting zygote has the correct diploid number of chromosomes.
What does PMAT stand for in mitosis?
PMAT stands for Prophase, Metaphase, Anaphase, and Telophase, the four stages of mitosis.
What happens during prophase?
During prophase, the chromosomes become visible, the nuclear envelope breaks down, and spindle fibers begin to form.
What happens during metaphase?
During metaphase, chromosomes line up along the center (equator) of the cell.
What happens during anaphase?
During anaphase, the sister chromatids are pulled apart to opposite sides of t
What happens during telophase?
During telophase, the chromatids reach the poles, the nuclear envelope reforms, and the cell begins to divide.
What is fertilisation?
Fertilisation is the fusion of a male gamete (sperm) and a female gamete (egg) to form a zygote.
Why is fertilisation important?
Fertilisation restores the diploid number of chromosomes and creates genetic variation in offspring.
Where does fertilisation occur in humans?
In humans, fertilisation usually occurs in the fallopian tubes.
What is meiosis?
Meiosis is a type of cell division that reduces the chromosome number by half, producing four genetically diverse haploid gametes.
How many divisions occur in meiosis?
Two divisions occur in meiosis: Meiosis I and Meiosis II.
What is the result of meiosis?
The result of meiosis is four haploid cells, each with half the number of chromosomes of the original cell.
How is genetic variation achieved in meiosis?
Genetic variation is achieved through processes such as crossing over (exchange of genetic material between homologous chromosomes) and independent assortment (random distribution of chromosomes).
How is meiosis different from mitosis?
Mitosis results in two genetically identical diploid cells, while meiosis results in four genetically different haploid cells.
