B2.5 Simple Inheritance In Animals And Plants Flashcards
Chromosome, DNA, nucleus, cell, base, gene
Put these in order from smallest to biggest
Smallest ------- Base Gene DNA Chromosome Nucleus Cell ------- Biggest
How many pairs of chromosomes does each cell have?
23 pairs
Define chromosome
Long section of DNA containing many genes and the instructions for lots of different characteristics
Define a gene
A small section of DNA containing the instructions for a single characteristic
What part of a cell contains the genetic material
The nucleus
What happens during mitosis?
Chromosomes copy each other and make a replicated strand. Spindle fibres are formed and you get each type of chromosome then they pull apart making two cells identical to the first
What are the female and male gametes called and where are they made?
Eggs/ova in the ovaries
Sperm in the testes
What happens during meiosis?
The chromosomes are copied, the cell divides into two and these new cells immediately divide again. This gives four sex cells each with a single set of chromosomes.
Does mitosis or meiosis give variety? And why is there variety?
Meiosis because in each sex cell they contain random mixtures of the original chromosome pairs
What happens during fertilisation?
Two sex cells join during fertilisation and the single cell formed has a full set of chromosomes (23 pairs-half sperm and half egg). The combination of genes on the chromosomes of every newly fertilised ovum is unique.
Asexual reproduction produces offspring as a result of ________
Sexual reproduction produces offspring as a result of ________
Mitosis
Meiosis
Define pluripotent
Embryo stem cell can become lots of things
What can stem cells become?
Nerve cells
Red blood cells
Muscle cells
Tissue cells
What are the pros of embryo stem cells?
Easy to collect and produce in a lab or embryos can be donated by IVF patients who don’t want them
People don’t need an operation to get them
Stem cells can turn into any cells
What are the cons of embryo stem cells?
Expensive
Embryo is destroyed which is a living thing - unethical
Pros of adult stem cells?
Can be taken out without destroying a potential life
Stem cells taken from an adult to be used by them will prevent rejection from happening
Cons of adult stem cells
Expensive
You need an operation to get them - harder to collect
Can only be turned into some types of body cells
Stem cells are _________ cells.
Undifferentiated
Why are stem cells important?
They could potentially produce every type of cell in the body
What’s therapeutic cloning?
Cloning by transferring the nucleus of an adult cell to an empty egg to produce tissues or organs which could be used in medicine
What are some problems with therapeutic cloning?
Could be unethical and it’s slow and very complicated
Who was Mendel?
An Austrian monk who closely studied the patterns of inheritance in pea plants.
He made these conclusions:
-Characteristics can be dominant or recessive
-Recessive characteristics may not show but can still be inherited
-certain characteristics can be inherited predictably
-inherited characteristics are passed on as bits of information called ‘factors’
What are Punnett squares?
They show each of the possible outcomes of characteristics
How would you represent a dominant characteristic?
Capital letter
How would you represent a recessive characteristic?
Lower case letter
What’s a genotype?
The genes
What’s a phenotype?
The physical way the genes look
What would the genotypes be if the dominant thing was SS and the recessive was ww
Sw, Sw, Sw, Sw
What would the genotypes be if the two genes were Sw and Sw
SS, Sw, Sw, ww
