Growth and reproduction Flashcards
What is another name for sex cells?
Gametes
How many chromosomes are there in the human body?
46 (23 pairs)
What are the 2 types of cell division?
Meiosis and mitosis
What is growth?
Growth of a multicellular organism is the increase in the size of the organism. This requires an increase in the number of cells
What is development?
Development refers to the process of change in an organism that leads to maturity. This process involves cells differentiating into specialised cells (eg. skin cells, muscle cells, liver cells, stomach cells etc) and then these specialised cells increase in number to form different tissues and organs
What is repair?
Repair is the process of restoring damaged tissue to a good condition; this resolves replacing damaged cells with new cells
What is mitosis?
Mitosis is cell division for growth and repair/replacement
How does mitosis work?
The first step is for the 46 chromosomes in the parent cell to replicate (copy themselves). Then the parent cell splits into 2. Each new daughter cell will have 46 chromosomes as well (genetically identical)
What are sister chromatids held together by?
Centromere
What is the cell cycle?
cell division (cytokinesis) — growth — mitosis (nucleus divides) — back to begining
What are the different stages of mitosis?
I - interphase (this isn’t part of mitosis this is a part of growth)
P - prophase
M - metaphase
A - anaphase
T - telophase
What are the stages of mitosis?
- Chromosomes replicate in the parent cell
- Chromosomes shorten and appear as chromatids joined by a centromere
- The nuclear membrane disappears. The chromosomes line up at the cells equator
- The chromatids are pulled apart to opposite poles by spindle fibres
- The nuclear membrane forms around each group of chromatids and the cytoplasm divides
- 2 daughter cells are formed
What is reproduction?
Formation of offspring - can be asexual or sexual
What is asexual reproduction?
It is when cells divide to make identical copies of themselves (mitosis). Asexual reproduction involves only one parent as there is no ‘sex’ involved. The offspring are genetically identical to the parent as they are clones
What is sexual reproduction?
It is the fusion of gametes that result in fertilisation. Sexual reproduction requires 2 parents and is slower than asexual reproduction. This results in genetic diversity (meiosis)
What is it called when bacteria reproduce asexually?
Binary fission
What are eukaryotic cells?
Genetic information held in a nucleus
eg. animals + plant cells
What are prokaryotic cells?
Genetic information that is not held in a nucleus
eg. bacterium
How does DNA arrange itself in eukaryotic cells?
DNA arranges itself as chromosomes in the nucleus of cells
What is a gene?
A section of DNA that codes for a certain characteristic
What does DNA stand for?
Deoxyribose Nucleic Acid
How many rounds of cell division happen in meiosis?
2
What is the purpose of mitosis?
To grow and repair + asexual reproduction
How many rounds of cell division happen in mitosis?
1
How many number of daughter cells are produced in mitosis?
2
Is there any genetic variation in mitosis?
No, cells produced genetically identical
Are mitosis cells diploid or haploid cells?
Diploid