SBI3U Test #1 Flashcards
(49 cards)
What are the 3 parts to a nucleotide?
A phosphate group, deoxyribose sugar, and a nitrogenous base.
What are the four types of nitrogenous bases?
Adenine, cytosine, thymine, and guanine.
What nitrogenous base is paired with cytosine?
Guanine.
What nitrogenous base is paired with adenine?
Thymine.
What is a nitrogenous base?
It is part of the “rungs of the ladder” in DNA. These include adenine, guanine, cytosine, and thymine. Each contain nitrogen.
What is a gene?
Genes are part of the chromosomes and are made of DNA. They control how certain traits are expressed in a cell and can be passed down to offspring. They determine things like hair colour or blood type.
What is a genome?
A genome contains all 46 chromosomes and has all the inheritable traits of the organism in it.
What is a chromosome?
It is a structure within the nucleus of the cell containing all the cell’s genetic information.
What are nucleosomes?
Nucleosomes are the units created by a strand of DNA coiled twice around histones.
What are chromatin?
They are nucleosomes that have been coiled into compact fibres.
Name 4 reasons why cells divide.
- To maintain an adequate surface area to volume ratio. Not having sufficient surface area means that wastes will accumulate and not enough needed materials (like glucose) will get into the cell.
- To increase the size of the organism
- To repair and replace damaged cells and tissues.
- In order to become specialized cells from stem cells.
What is a nuclear membrane?
It is a membrane around the nucleus that controls what goes in and out of the cell, and keeps the contents of the nucleus inside.
What is the nucleolus?
It is the part of the nucleus that makes ribosomes. (Ribosomes are used to make proteins)
What are centrioles?
As a pair, centrioles are called the centrosome. They construct the micro-tubules that become spindle fibres.
What are chromatin?
Chromatin are DNA in its decompacted (unwound) state.
What are the sister chromatids?
They are duplicate copies of chromatid held together by the centromere to form a chromosome as a whole.
What are spindle fibres?
Spindle fibres are of micro-tubules by the centrioles. They are used to line up the chromosomes along the equatorial plate and pull them apart at the centromeres. (Like the fishing line if the centriole was the fisherman and the centromere was the fish.)
What are micro-tubules?
They are the material used to make up spindle fibres.
What are chromosomes?
They are compacted DNA.
What is the aster?
The aster is the centriole with spindle fibres forming out of it. (looks like a spider or an aster flower)
What is the equatorial plate?
The equatorial plate is the imaginary line across the cell that the sister chromatid line up on in during metaphase.
What are the 3 stages of DNA replication?
- Helicase unzips the parent strand by breaking the hydrogen bonds between the base pairs
- Enzymes help free-floating nucleotides bond following pairing rules
- Enzymes reattach the backbone of deoxyribose sugars and phosphates.
What are 2 causes of mutations?
Spontaneous and Mutagens
How and why to spontaneous mutations occur?
They occur under natural condition due to miss-pairing in DNA replication, nondisjunction (chromosome pairs do not separate properly during cell division)
