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AICE Biology
Cell cycle and genetic control
Question | Answer |
---|---|
How does the structure of DNA differ between a dividing and non dividing cell? | non dividing cells: DNA is slender, activity changes, gene turns on and off. |
What 2 things does a chromosomes consist of? | DNA and protein |
What is length of DNA that codes for a specific function or structure? | Gene |
What is a telomere? | A compound structure at the end of a chromosome, caps at the end of each strand of DNA which protects chromosomes. |
When are identical sister chromatids formed? | S phase of interphase |
What is the difference between euchromatin and heterochromatin? | Euchromatin: chromosome material that does not strain strongly except during cell division, rep. major genes. Heterochromatin: chromosome material of diff. density from normal, in which genes is modified. |
What are two main things that happen during interphase? | S phase: copies DNA, proteins package of DNA, more cell membrane material. G phase: organelles divide, more ribosome |
When does DNA replication occur? | interphase |
When does protein synthesis occur? | S phase interphase |
When does cell growth occur? | constantly but in interphase |
How is a multinucleate cell formed? | By the fusion of multiple cells to form one much bigger cell (syncytium) and repeated nuclear division without cytokinesis forming cells (coenocytes) |
What are stem cells and where there are they found? | an undifferentiated cell of a mulitcellular organism that is capable of giving rise to indefinitely more cells of the same type. in tissue like liver and brain. |
What are equivalent of stem cells? | meristematic tissue and cambium. |
Why must replication occur before a cell divides? | B/C 2 strands of DNA molecule have complementary base pairs, the nucleotide sequence of each stand automatically supplies the information needed to produce its partner. |
What is meant by the term 'semi- conservative' replication? | 1/2 new and 1/2 old Dna helix |
What does DNA polymerase? | enzyme that synthesize DNA molecules from deoxyribonucleotides. |
What does DNA ligase? | facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond. |
What is an activated nucleotide? | nucleotide in the nucleus with 2 phosphate. |
Does replication occur in the same direction for both strands of DNA? | No, they go opposite directions. |
What are the functions of telomeres? | to protect ends of chromosomes and prevent one chromosome form binding to another. |
What does telomerase do? | Elongates the chromosomes and effects aging. Adds nucleotides to telomeres. |
What are the five functions of mitosis? | Growth of an organism, repair tissue, replacement, cell division, and production of genetically identical cells. |
What is tissue? | any of distinct types of material of which animals or plants are made, consisting of specialized cells and their products. |
If daughter cells are not identical to parent cells, what might the immune system do? | Immune system will attack and non identical cells and get rid of them. hurting the body |
What do the terms 'clone' and 'vegetative propagation' mean? | Clone: an organism or cell, or group of organisms or cells produced asexually which is genetically identical to ancestor. Vegetative propagation: asexual reproduction of a plant, only one plant is involved. |
What can uncontrolled cell growth result in? | a tumor which can turn into cancer. |
How do cells have different functions and structures? | different genes which give specific directions |
The difference between cytokineses for plant and animal cells? | Animal: cleavage is formed first in middle of cell then it deepens till the membrane and cell divides. Plant: row of vesicles develops. |
What do spindle fibers do? | form a protein structure that divides the genetic material in a cell. They move chromosomes to poles form the middle. |
Which organelle related to cell division do animal cells have that plant cells do not? | centrioles |
What is root cap? | protects the growing root tip |
What is meristematic area? | above root cap |
What is zone of elongation? | in the middle |
What is zone of differentiation? | at the top |
The difference between a gene and a polypeptide? | Gene: basic physical and functional unit of heredity polypeptide: linear organic polymer, large # of amino acid residues bonded together in a chain. |
What does coded mean in terms of DNA and primary structure of a protein? | the sequence in it that make the protein, DNA has specific activity. |
What is gene mutation? | causes a single nucleotide base substitution, insertion, or deletion of the genetic material. |
Primary structure determines | shape and function |
What is transcription | the first step of gene expression, particular segment of DNA is copied into mRNA by the enzyme RNA polymerase |
What is translation | mRNA is translated into proteins. |