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what does DNA stand for?
cells containing only on set of chromosomes
haploid reproductive cells such as eggs or sperm
a complex of uncoiled DNA and proteins within the nucleus
a cell containing two sets of chromosomes; one set inhereted from each parent
fusion of a haploid sperm with a haploid egg
what molecules make up the backbone of DNA?
sugar and phosphate
what molecules is a single nucleotide composed of?
what type of bond holds the three components of the nucleotide together?
- deoxyribose sugar
- nitrogenous base
- ==> covalent bonds
list the four nitrogenous bases of DNA:
a change in the genes and the characteristics of an organism due to the inclusion of external DNA by a cell
a display of the chromosome pairs of a cell arranged by shape and size
which bases are purines?
- Adenine and Guanine
- ==> larger two ring structure
which bases are the pyrimidines?
- Thymine and Cytosine
- ==> smaller single ring structure
each strand of the double-stranded helix is oriented in an opposite direction. this orientation is termed:
a chromosome not directly involved in determining the sex of an organism
its three functions:
- the reproduction of a cell
- 1. growth of a new organism
- 2. the replacement of old or damaged cells
- 3. asexual reproduction
the division of a single nucleus into two genetically identical daughter nuclei
the division of the cytoplasm to form two separate daughter (new) cells
the five phases of mitosis:
chromosomes exist as long thin threads of DNA and proteins tangled together in the nucleus
nuclear membrane dissipates, microtubules form to attach to the centromeres of each chromosome
the microtubules have attached to the centromeres and arrange the chromosomes along the equator ("metaphase plate") of the cell
- the centromere of each sister chromatid is pulled to the poles of the cell, each is now referred to as a chromosome
- the microtubules drag the centromeres of each chromosome, making the chromosomes appear V-shaped.
- by the end of anaphase, two identical complete sets of chromosomes have reached the poles
- begins with two groups of chromosomes at the opposite poles of the cell
- the chromosomes begin to uncoil and relax
- nuclear envelope begins to reform
- cytokinesis begins - the division of the cytoplasm and a new cell plate is formed
state two ways in which mitosis is different in animal cells than in plant cells:
- 1. centrioles - anchor microtubules
- 2. cleavage - no cell wall