Cell division And Diversity Flashcards
what is cell continuity
every cell develops from existing cells.
what is a chromosome
a structure which consists of protein and DNA that carries genetic information in the form of genes
what is chromatin
condensed chromosomes that are seen in the cell when not dividing
what is a gamete
a sex cell
what is a gene
a short section of DNA that codes for a protein
what is junk DNA
DNA that doesnt code for a protein
what is the genome
all the genes in the organism
what is the locus
the position of a gene on a chromosome
how many chromosomes in a human cell
46, 23 pairs
what are a homologous pair of chromosomes
a pair of chromosomes which have the same types of genes at the same loci, one from the mother, one from the father
what are sister chromatids
chromosomes that are identical to each other stuck together by a centromere, they are produced in late interphase by DNA replication
what is interphase
the non dividing phase of the cell, the cell is in this phase for 90% of its cycle
what occurs during early interphase
normal cell functions and replication of cell organelles
what occurs in late interphase
DNA is replicate on each chromosome producing an identical copy of each chromosome, the copied chromosome is stuck to the original by the centromere which holds the two identical chromosome together
what happens during prophase
the nuclear membrane disintegrates, chromosomes become visible from chromatin, spindle fibres appear in cytoplasm
what occurs in metaphase
the spindle fibres move to the poles of the cell, chromosomes align along the equator of the cell, spindle fibres become fully formed and attach to the centromeres
what occurs in anaphase
spindle fibres contract, splitting the centromere and pulling apart the identical chromosomes, chromosomes pulled back to the poles of the cell
what occurs during telophase
nuclear membrane forms around chromosomes at each pole, spindle fibres disappear, chromosomes begin to become chromatin again
what occurs for animal cell during cytokinesis
groove forms in cytoplasm called cleavage furrow which deepens until it splits into 2 identical cells
what happens to plant cells during cytokinesis
cell plate forms from the vesicles in plant cells, a middle lamella forms in the cell plate to divide the two identical cells
what is the function of mitosis
unicellular is used for reproduction eg binary fission and multicellular is used for growth and repair
what is cancer
a group of disorders in which cells lose control over the rate and number if divisions they undergo, this results in the uncontrolled multiplication of cells
what are the causes of cancer
carcinogens and oncogenes
what is the treatment for cancer
chemotherapy, radiation and surgery
what is meiosis
nuclear division in which one nucleus divides to form four nuclei with half the number of chromosomes
what is the function of meiosis
to produce gametes or haploid cells in sexual reproduction so the parental chromosome is the same after sexual reproduction and to introduce variation in species.
What is an organ?
A group of tissues with the same functions working together.
E.g. Plant: Leaf, stem or e.g. Animal: Heart, Liver
What is a system?
A group of organs with similar functions that work together. (Digestive System)
What are plant tissues?
Xylem and dermal.
What is Xylem?
Xylem found in the vascular tissue of a Stem and veins in leaves. Dead cells, contents hollow. Cell wall contains lignin. Transports water. Has Continuous side pits to allow water to pass from cells which are side by side.
What is Dermal Tissue?
Outside layer of tissue in plant (epidermis). Function is primarily protection. Cell wall is thick sometimes has a waterproof layer called a Cuticle in leaves and stoma
What are animal tissues?
Connective tissue and nervous tissue
What is Connective Tissue?
Found in many areas (Bone, Blood, Cartilage). Many functions -R.B.C’S function is to carry oxygen around the body. Many types -R.B.C is concave in shape, has no nucleus or mitochondria.
What is Nervous Tissue?
the tissue that makes up the brain, spinal cord, and nerves. It is responsible for transmitting electrical impulses and enabling communication between different parts of the body.
What are the uses of Tissue Culturing?
- Micropropagation
- Cancer Research
- Skin Grafts
What is Tissue Culturing?
Tissue Culturing is a method where cells are grown in a sterile nutrient medium outside an organism. Usually Involves: Nutrients, Oxygen, Sterile Conditions, Growth Substances. Optimum Growth Conditions such as temperature and pH.
What is Micropropagation?
Micropropagation is the use of tissue culturing to produce many genetically identical organisms.
Benefits of micropropagation:
all organisms are genetically identical and produces large numbers of plants very quickly.
Disadvantages of micropropagation:
susceptible to disease due to lack of variation as they are genetically identical and its expensive.
