B13 :Reproduction Flashcards
what are the two ways of reproducing
sexual and asexual
how many parents does asexual reproduction involve
1
during asexual reproduction, how do cells divide
mitosis
asexual reproduction means there is no…..
variation in offspring
in the body, why do your cells asexually reproduce
growth and replacing worn-out tissues
what does sexual reproduction involve
the fusion of gametes
what does a male sex cell and female sex cell first form
zygote (really early baby)
how are gametes formed?
meiosis
does sexual reproduction have variation
yes
what are the gametes in plants
egg cells and pollen
what are the gametes in animals
ova (egg) and sperm
what happens during meiosis
-the genetic information is copied so there are four sets of chromosomes. Each form a pair of chromatids
-Then, the cell divides twice quickly to form 4 gametes.
- each gamete has a single set of chromosomes
how many chromosomes do human gametes have
23, join to form 46
pros of asexual
-one parent needed, efficient
-faster
cons of asexual
NO genetic variation
cons of sexual
two parents needed, not efficient
slower
pros of sexual
natural selection, surviving changes in environment
how do fungi reproduce
asexually AND sexually
what is fungi made of (thin threads)
hyphae
gamete for fungi
haploid spores
example of plant that reproduces asexually
runners and daffodils
where do malarial parasites reproduce asexually
human liver and blood cells
where do malarial parasites reproduce sexually
IN the red blood cell, due to the drop in temperature
what does DNA stand for
deoxyribonucleic acid
what do the gene codes control
a sequence of amino acids that form a specific protein
genome:
entire genetic material of the organism
how does understanding the human genome help us
-understand inherited disorders
-finding genes linked to different types of disease
-understanding human evolution, finding common ancestors
what is DNA made of
alternating sugar and phosphate sections
what are the four compounds on DNA known as
bases
what letters represent the bases
A,G,C,T
combination of sugar, phosphate and base
nucleotide
C-
G
T-
A
how do the templates for proteins get to the ribosomes
-leaves the nucleus through the pores in the cell membrane
-binds to the ribosome
-cytoplasm contains carrier molecules, each attached to specific amino acids.
-the carrier molecules attach themselves to the template in the correct order.
-amino acids join together to form protein
-keeps going and makes a chain
what happens once the protein chain is made
fold up to take the form of unique product (e.g active site)
what are the non-coding parts of DNA involved in
switching genes on and off
cons mutation
folds into a different function and cannot carry out necessary function
pros mutation
may produce more efficient and stronger things.
homozygote
two identical alleles (AA,aa)
heterozygote
two different alleles (Aa)
genotype
alleles present regarding a particular characteristic
phenotype
physical appearance (e.g. blue eyes)
result of genes
why are Punnett squares not 100% accurate
it is only the predicted phenotypes, gametes carry random ones each time
male and female sex chromosomes
m XY
f XX
extra fingers and toes disease
polydactyly
is polydactyly recessive or dominant
dominant
is cystic fibrosis recessive or dominant
recessive
what does cystic fibrosis do
thick mucus around lungs, digestive system ect.
pancreas cant secrete enzymes.
infertility
treatment of CF
antibiotics and physiotherapy
enzymes use in CF
used to replace once that aren’t made and thin the mucus
how is a future way of helping genetic disease
genetic engineering
what are the two main methods of screening embryos
-amniocentesis
-chorionic villus sampling
amniocentesis
15-16 weeks of pregnancy
taking fluid from around fetus that contains fetal cells for genetic screening
chorionic villus sampling
10-12 weeks of pregnancy
small sample of tissue from placenta that provides fetal cells
alternative way for pregnancy with inherited disease
IVF
cons of embryo screening
-risk of miscarriage increases
-can give false results
-ethical issues if termination
-expensive
-rise of ‘designer babies’, wanting the perfect baby
