B13

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What is asexual reproduction? ( 3 facts)
Only involves one parent, cells divide by mitosis, no gamete fusion,
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What is sexual reproduction? ( 3 facts)
Gametes fuse, cells divide by meiosis, two parents
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What are the gametes in plants?
Egg cells and pollen
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Why is their variation through sexual reproduction?
Two diff cells, diff genetic info
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What is the first step in meiosis?
Genetic info copied, 4 sets of each chromosome
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What does each chromosome form a pair of?
Chromatids
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What is the second step in meiosis?
Cell divides quick to form four gametes each with single set
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What is each gamete?
They are different to each other genetically
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What is an advantage of asexual reproduction?
Time + energy is efficient no need to find mate or spread gametes, also is faster than sexual
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What is a disadvantage of asexual reproduction?
If environment change no organism survive
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What is an advantage of sexual reproduction?
Variation in offspring
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What is natural selection?
Where variation offers survival advantage
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What reproduction type do fungis do?
Asexual
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What are many fungi made up of and what are they called?
Thin threads called hyphae
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When can fungi reproduce sexually?
When conditions are bad
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What are some examples of plants that reproduce asexually?
Strawberry plants
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What is a disadvantage of this?
New plants identical to parents, no variation
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Where do malarial parasites reproduce asexually?
Liver + blood cells
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What triggers sexual reproduction?
Drop in temp
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What happens during this drop in temp and how long?
Between 20mins, sexual forms burst out and form zygote that undergoes meiosis to form new parasites
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What are genes?
Small sections of the DNA
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What does each chromosome contain?
Thousands of genes
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What is the genome?
The entire genetic material of the organism
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What can understanding the human genome help us understand?
Inherited disorders e.g. sickle cell + cystic fibrosis
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What is DNA made up of?
Alternating sugar + phosphate sections, make up backbone and double helix
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What are bases?
They are attached to the sugars
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What are the letters for the bases?
ACGT
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What is a nucleotide?
The combination of a sugar, phosphate and a base
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What base pairs go together?
AT and GC
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What do the genes in the DNA produce?
A template for the protein
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What does the template reflect?
Sequence of bases in DNA but is small enough to leave nucleus through pores in nuclear membrane
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What is the first step in making this protein?
Template leaves nucleus + binds to surface of ribosome
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What is the second step in making this protein?
Cytoplasm contains carrier molecules attach to a specific amino acid, these attach to template
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What is the third step in making this protein?
The amino acids join together to form a specific protein
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What is the fourth step in making this protein?
Carrier molecules keep bringing specific amino acids to add to growing protein chain in correct order till complete
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What is the fifth step in making this protein?
Protein detaches from carrier molecules ad they go back to cytoplasm
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What happens when finished?
Folds depending on what protein e.g. enzyme folds to make active site
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What are mutations?
Tiny changes in the sequence of bases in strand of DNA
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What can a few mutations code for?
Change in amino acids which alters folds to give diff shape
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What is the consequence of this?
Active site may no longer fit substrate or structural protein lose strength
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What can mutations also do?
Give an advantage e.g. more efficient enzyme or stronger protein
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What are alleles?
The different forms of genes e.g. eye colours
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What is a homozygote?
Two identical alleles, e.g. BB or bb
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What is a hetrozygote?
Two different alleles, e.g Bb
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What is a genotype?
Describes alleles present, Bb or bb
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What is phenotype?
The physical appearance which is expressed
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What letters represent what type of action?
Capital for dominant, lowercase for recessive
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What are the sex chromosomes like for female?
Same, **
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What are the sex chromosomes like for male?
Different, XY
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What is polydactyly?
Extra fingers or toes
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What is the most common cause of it?
Dominant allele, inherited from one parent
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What is cystic fibrosis?
Genetic disorder effecting many organs of body
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What are some treatments for cystic fibrosis?
Physiotherapy and antibiotics
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What is cystic fibrosis caused by?
Recessive allele must be from both parents
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What do scientists hope will cure?
Genetic engineering
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What test is carried out at 15-16 weeks preggo?
Amniocentesis
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What happens during this?
Fluid around fetus taken used for genetic screening
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What test can be carried out at 10-12 weeks prego?
Chorionic villus
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What happens during this?
Tissue taken from placenta
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What is a disadvantage of these tests?
Can cause miscarriage
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What is another way for IVF people to test?
Have embryo tested before implantation
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What are disadvantages of the screenings?
Miscarriage of healthy baby, false readings, terminating babies, expensive, lead to designer babies,
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Other cards in this set

Card 2

Front

What is sexual reproduction? ( 3 facts)

Back

Gametes fuse, cells divide by meiosis, two parents

Card 3

Front

What are the gametes in plants?

Back

Preview of the front of card 3

Card 4

Front

Why is their variation through sexual reproduction?

Back

Preview of the front of card 4

Card 5

Front

What is the first step in meiosis?

Back

Preview of the front of card 5
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