B13(Reproduction) Flashcards
What is asexual reproduction
-There is no fusion of gametes and only parent
-there is no mixing of of genetic information, leading to genetically identical offspring
What is sexual reproduction
-Involves the fusion of male and female gametes formed by meiosis
-there is a mixing of genetic information that leads to variation in the offspring
What is mitosis
Cell division resulting in 2 identical cells with exact copies of all the chromosomes
What is meiosis
A special form of cell division resulting in 4 differing sex cells being formed
What is fertilisation
When 2 sex cells join and dna forms a single nucleus
What are the advantages of asexual reproduction
Quicker, many identical offspring, lower risk, no need to find mate,lower energy requirement
What is a disadvantage of asexual reproduction
No variation
What are the advantages of sexual reproduction
-More variation in offspring
-this variation gives a survival advantage if environment changes
What are the disadvantages of sexual reproduction
-much more risky
-relies on 2 cells fusing
-time and energy is used to find a mate
-greater energy requirement
What is a haploid
Cells containing one version of each chromosome
What is a diploid
Cells containing pairs of chromosomes
What is a zygote
When gametes fuse
What is DNA
-The genetic material in the nucleus of a cell
-2 long strands wound together in a double helix
What are base pairs
-Pairs of bases held together by hydrogen bonds
-3 pairs gives the code for an amino acid
What are the 4 bases
A
T
C
G
What are the pairs of the bases
A and T
C and G
What is a gene
-A specific section of DNA on a chromosome
-code for a specific sequence of amino acids
What are chromosomes
Long chains of DNA that contain thousands of genes joined together
What are nucleotides made from
-phosphate group
-ribose sugar
-nitrogenous base
What is the process to make proteins
-DNA in the nucleus is used to produce a template
-The template leaves the nucleus and binds to a ribosome
-carrier molecules bring specific amino acids and attach themselves to the template
-The amino acids join together to make a protein
-Repeats step 3 and 4 until the entire protein chain is assembled
-protein detaches and the carrier molecules collect more amino acids
-protein then folds up to its specific shape
What are mutations
changes in the sequence of bases in a strand of DNA
What is an Allele
Different versions of the same gene
What does heterozygous mean
-The 2 alleles are different
-for example a person can have a blue eye allele and one brown eye allele
What does homozygous mean
-The 2 alleles are the same
-for example a person can have 2 blue eye alleles
