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what does DNA stand for?
deoxyribonucleic acid
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haploid
cells containing only on set of chromosomes
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gamete
haploid reproductive cells such as eggs or sperm
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chromatin
a complex of uncoiled DNA and proteins within the nucleus
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diploid
a cell containing two sets of chromosomes; one set inhereted from each parent
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fertilization
fusion of a haploid sperm with a haploid egg
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what molecules make up the backbone of DNA?
sugar and phosphate
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what molecules is a single nucleotide composed of?
what type of bond holds the three components of the nucleotide together?
- deoxyribose sugar
- phosphate
- nitrogenous base
- ==> covalent bonds
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list the four nitrogenous bases of DNA:
- Adenine
- Guanine
- Cytosine
- Thymine
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transformation
a change in the genes and the characteristics of an organism due to the inclusion of external DNA by a cell
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karyotype
a display of the chromosome pairs of a cell arranged by shape and size
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which bases are purines?
- Adenine and Guanine
- ==> larger two ring structure
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which bases are the pyrimidines?
- Thymine and Cytosine
- ==> smaller single ring structure
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each strand of the double-stranded helix is oriented in an opposite direction. this orientation is termed:
anti-parallel
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autosome
a chromosome not directly involved in determining the sex of an organism
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cell division:
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
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mitosis
the division of a single nucleus into two genetically identical daughter nuclei
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cytokinesis
the division of the cytoplasm to form two separate daughter (new) cells
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the five phases of mitosis:
- interphase
- prophase
- metaphase
- anaphase
- telophase
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interphase
chromosomes exist as long thin threads of DNA and proteins tangled together in the nucleus
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prophase
nuclear membrane dissipates, microtubules form to attach to the centromeres of each chromosome
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metaphase
the microtubules have attached to the centromeres and arrange the chromosomes along the equator ("metaphase plate") of the cell
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anaphase
- 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
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telophase (cytokinesis)
- 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
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state two ways in which mitosis is different in animal cells than in plant cells:
- 1. centrioles - anchor microtubules
- 2. cleavage - no cell wall
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