biology Flashcards
chromosome
the thread like structure of DNA containing the genes
double helix
shape like a twisted rope ladder, made of two sugar phosphate backbones
DNA
- deoxyribonucleic acid
- the compound chromosome are made of
- it is the blueprint of life, tells the body what, when and how to build something how much to build and how long for
diploid
2n
46 in humans, 44 autosomes and 2 sex chromosomes
haploid
n
23 egg and sperm
gamete
sperm and egg cells
gene
- portions of dna make up genes
- contains your traits and characteristics
mitosis
- cell division for growth or repair
- same chromosome number
mutation
a mistake that happens when dna is being copied causing damage to the base sequence
nucleus
where chromosomes are found
nucleotide
- one portion of a stand of dna
- made up of deoxyribose sugar, phosphate and a base
nitrogenous base
- part of a nucleotide
- four types
phosphate
one of the parts that make up a nucleotide
replication
process of copying cells
molecules of the nucleus
all living things have slightly different versions of the same molecules in the nucleus of their cell
what is dna and what does it do
- deoxyribonucleic acid
- controls the way organisms look and function
- determines characteristics
- contributes to the diversity and variety of living things
- has similar structure in all organisms
what is a nucleotide
- the basic building block of dna
- has three parts, base, deoxyribose sugar and phosphate
- arranged in such a way that gives the dna molecule a double helix
- the bases always pair in the same way
first stage of cell division
-
diploid number
human body cells each contain 23 pairs or 46 chromosomes
what is a chromosome made of
- composed of many genes
- genes are sections of dna
what is the difference between one gene and another
the number and order of the bases along the dna stand
what does a gene contain
a gene contains the code for building a protein which controls a characteristic or function in the body
what is mutation
mutations are changed in the bases of genes or to chromosomes
what is mitosis
- is cell division in the body cells for growth and repair
- it produces two identical cells
how do remember the stages of mitosis
i party most at the club
what are the six stages of mitosis
- interphase
- prophase
- metaphase
- anaphase
- telophase
- cytokinesis
what does the first stage do
- dna coils up
- doubling the dna
- 46 turns to 92 which are sister chromatids
what happens in the second stage
- the replicated chromosome and their chromatids become visible
- membrane disappears
- they link together
what happens in the third stage
replicated chromosomes line up along the middle of the cell - original on one side - duplicated on the other but still joint together - attached to a fibre (line)
what happens in the fourth stage
- the chromatids separate and move to opposite poles of the cell
- each chromosome split in half
what happens in the fifth stage
2 nuclei form each with the same number of chromosomes as the parent cell
what happens in the sixth step
- cell membranes form making 2 daughter cells
- each with a nucleus
what is a chromatid
- when they are duplicated and then join with the duplicated chromosome
allele
different version of the same gene
what are the four bases
thymine
adenine
cytosine
guanine
