Unit 5 Cellular Reproduction Flashcards
What is cell division
splitting of the parent cell into two identical daughter cells
What is asexual reproduction
Cell division that results in the reproduction of a whole organism
-cloning
What is sexual reproduction
reproduction that requires the fusion of gametes
What are the steps of binary fission
Dividing in half
-happens in prokaryotes
What are gametes
egg and sperm cells
What is a zygote
Fertilized egg
What is the cell cycle
sequence of events from the instant a cell is formed to the moment it divides into two new daughter cells
What are the 2 main stages of the cell cycle
- Interphase: growing phase
-90% of cell cycle - Mitotic phase: Cell division
what are the 3 phases of interphase
- G1 phase: first gap
- S phase: synthesis phase
- G2 phase: Second gap
What happens in G1 phase
-normal cellular functions take place
What happens in S phase
DNA replication takes place
What happens in G2 phase
-cell finishes preparing for cell division
What are the 2 stages of the Mitotic phase
- Mitosis
- Cytokinesis
What is mitosis
The division of the nucleus and its continents
What is cytokinesis
the division of the cytoplasm and separation of the 2 daughter cells
What happens in Prophase
- Chromatin coils into chromosomes
- mitotic spindle emerges from the centrosomes
- centrosomes separate
What happens during Prometaphase
- Nuclear envelop disappears
- Mitotic spindle ends reach chromosomes
- some attach to the middle of the chromosome
What happens during Metaphase
- Chromosomes line up on the metaphase plate
(imaginary line in the middle)
What happens during Anaphase
- Chromosomes come apart and the sister chromatids separate
What happens during Telophase and Cytokinesis
- Daughter nuclei are formed at the poles of the cell
- Mitotic spindle disappears
- Mitosis is finished
What happens during cytokinesis in animal cells
a Cleavage Furrow:
-microfilaments and myosin form a ring at the furrow site
-Furrow deepens and eventually pinches the parents cell into 2
What happens during cytokinesis in plant cells
Vesicles transport new cell wall material to the middle of the parents cell
- creates a divider between the two daughter cells
What are the environmental factors that influence cell division
- Anchorage dependance: must be in contact with a solid surface to divide
- Density-dependent inhibition: crowded cells stop dividing
- Chemical factors: need certain nutrients to grow
- Growth factors: divide if certain proteins are present
What are tumors
mass of abnormally growing cells within a normal tissue
What are the 2 different types of tumors
Benign tumor:
-abnormally cells remain at their original location
Malignant tumor:
-Abnormally reproducing cells that can spread into other tissues in other part of the body
what are Somatic cells
Typical body cells
- human somatic cells have 46 chromosomes
What are Homologous Chromosomes
- match in length, centromere position and staining pattern
- carry same genes for the same inherited characters
What are sex chromosomes
chromosomes that determine the sex of an individual
What are Autosomes
All other chromosomes other than sex chromosomes
- humans have 44 autosomes (22 sets of homologous chromosomes) and 2 sex chromosomes
What are Diploid cells
A cell that contains two sets of chromosomes
abbreviated to 2n
What are Haploid cells
A cell with a single set of chromosomes
humans: 1n = 23
-occurs in gametes
What is the life cycle
sequence of stages for an organism from fertilization until the production of its own offspring
What are the stages of Meiosis
- Interphase: chromosomes are duplicated
- Meiosis 1: the first division takes place
- Meiosis 2: The separation of the two sister chromatids
What happens during interphase in meiosis
- chromosomes duplicate
- centrosome duplicates
What happens during Prophase 1 in meiosis
- homologous chromosomes come together as pairs
- crossing over
- chromosomes coil tightly and a spindle forms
What happens during Metaphase 1 in meiosis
- Chromosome tetrads are aligned at the metaphase plate
What happens during Anaphase 1 in meiosis
- Chromosomes migrate to the two poles of the cell
- sister chromatids of a chromosome stay attached to each other
What happens during telophase 1 and cytokinesis in meiosis
- each pole has a haploid chromosome set
- cytokinesis (same as mitosis)
-to haploid daughter cells are formed
What happens during meiosis 2
Prophase 2: spindles move chromosomes to the center of the cell
Metaphase 2: chromosomes are aligned at the metaphase plate
Anaphase 2: centromere of sister chromatids separate and move to opposite poles
Telophase 2 and cytokinesis: nuclei form at the cell poles and the cell undergoes cytokinesis
(Making 4 haploid daughter cells)
what are recombinant chromosomes
chromosomes that carry DNA from 2 different parents
How to calculate combinations of chromosomes
What is the process of nondisjunction
When chromosome pair fails to separate
- in meiosis 1; the homologous chromosome stay together and dont go to opposite poles
-half of gametes get 2 of the same chromosome - half gametes do not get that chromosome at all
What is deletion
chromosome fragment becomes detached
What is duplication
Chromosome fragment that detaches and attaches to the sister chromatid
what is inversion
chromosome fragment reattaches to the same chromosome but in reverse orientation
What is Translocation
Fragment joins a non-homologous chromosome
