DNA and genes Flashcards
what is genetic information?
a chemical blueprint that codes for characteristics of an organism
what does a DNA molecule contain?
bases which are arranged in complementary pairs. DNA transcripts into RNA and then translated into protein.
how many chromosomes do most humans have?
46 individual chromosomes
when does fertilization occur?
when a sperm fuses with an egg
what is the difference between recessive and dominant characteristics?
the dominant characteristic always masks the recessive characteristic (eg AA, Aa will have a a phenotype of A)
what is the difference between mitosis and meiosis?
mitosis has 2 identical daughter cells that contain 46 chromosomes and produce body cells.
meiosis has 4 non-identical daughter cells that contain 23 chromosomes and produce sex cells.
what are the phases of mitosis?
prophase, metaphase, anaphase, telophase
what happens in mitosis?
Interphase is the preparation for cell division, it replicates the chromosomes.
Prophase is when DNA condenses to form chromosomes
Metaphase is when the chromosomes line up
Anaphase is when the chromosomes split up
Telophase is when the nucleus reforms
what phase sets up mitosis?
interphase
what is the longest phase of the cell cycle?
interphase
what is a phenotype?
the physical appearance of the genes (eg blue eyes, black hair)
what is a genotype?
the genes of an organism. (eg AA, Aa, aa)
how are females and males represented on a pedigree? how do you interpret a pedigree?
circle for female, square for male.
what is the difference between heterozygous and homozygous?
hetrozygous is when the alleles are different (Aa). homozygous is when the alleles are the same (AA, aa)
what is the complementary pairing of bases?
A and T, G and C
what does DNA stand for?
deoxyribonucleic acid
what is the structure of DNA?
DNA is two nucleotide strands that wound together to form a double helix shape
what is the difference between DNA and RNA?
DNA has 2 stands and has thymine (T)
RNA is single stranded and has Uracil (U)
during DNA transcription A complementary pairs to U
if the first base triplet has a mutation occurring with adenine being replaced by cytosine. What effect will it have on the amino acid coded for?
this will change the amino acid
what is a gene made up of?
a gene is made up of DNA
what is an allele?
a different type of gene
how is the cross between two heterozygous white sheep shown on a punnet square?
W on the top left, w on the top right, W on the top left side, w on the bottom left side. then work out the percentages.
what are haploid cells?
sex cells
what are diploid cells?
body cells
what are chromosomes?
they are found in the nucleus
what makes up a nucleotide?
phosphate group, pentose sugar, nitrogenous base,
what is X X and X Y?
XX = female, X Y = male
the name of the building block for DNA?
nucleotide
what is the outcome of mitosis?
cytokinesis
what is the percentage of all bases in a molecule?
C and G = 15% A and T = 35%
what is the function of DNA?
DNA determines the structure and functioning of an organism.
DNA can track back genes and inheritance
what are the building blocks of protein?
amino acids
what are genes?
genes are inherited by parents and determine someones characteristics
