genetics, epigenetics and microbiome Flashcards
what is the genome
all the genes
what is gemtogenesis
gamete cell division called meiosis
where does gametogenesis
gonads (testes and ovaries)
how many daughter cells are produced in meiosis
4
what does haploid mean
singular set, not a pair
what happens to the sperm once the sperm enters the ovum
nucleic membrane of sperm breaks down and male chromosomes are released
what does the embryo start as
zygote
what then happens to the zygote
it grows - doubles day 2, then doubles day 3
what does the zygote then become
embryo
what does the embryo then become after doubling
morula
what does the morula then become after doubling
blastocyst
what are chromosomes
structures that store information needed for structure, function, reproduction and development of an organism
how many pairs of chromosomes are there in a human
23 pairs
how do most cells divide
mitosis
how many daughter cells does mitosis provide
2 identical daughter cells
how do gamete cells divide
meiosis
what is cytogenics
the study of chromosomes
what is karyotyping
process of examining chromosomes
what does an abnormal number of chromosomes after fertilisation result in
miscarriage as embryo cannot develop
what percentage of pregnancies miscarriage
15%
what percentage of miscarriages have had chromosomal abnormalities
50%
who is mDNA inherited from
mother
why is mDNA not inherited from the father
the mDNA is situated on the neck of the sperm which does not enter the oocyte
what can errors in the mDNA cause
rare disorders
what does DNA stand for
deoxyribose nucleic acid
what is a gene
segment of DNA that contains the code for a specific protein that functions in one or more types of cells in the body
do chromosomes contain genes
yes
what is an allele
different versions of the same gene
what does heterozygous mean
2 different alleles
what does homozygous mean
2 alleles which are the same
what is phenotype
visible characteristics
what is genotype
actual characteristics usually written as a series of bases
what does trisomy mean
3 chromosomes of 1 type
what does monosomy mean
1 chromosome only
what does deletion mean
fragment of chromosome missing
what is translocation
fragment of 1 chromosome breaks off and joins w/ another
reciprocal translocation
2 chromosomes exchange fragments w/ each other
what does ffDNA stand for
free fetal DNA testing
what does NIPT stand for
non-invasive prenatal testing
how is ffDNA testing done
sample of maternal blood obtained and fragments of fetal DNA extracted
why is ffDNA testing done
to determine genetic abnormalities + rhesus status
when can rhesus status be detected
16-20/40
what is the risk of amniocentesis + chorionic villi
miscarriage
what is amniocentesis
extracting amniotic fluid so cells it contains can be tested
define chorionic villus sampling
removing and testing a small sample of cells from the placenta
what causes down’s syndrome
trisomy 21
what causes edwards syndrome
trisomy 18
what causes patau’s syndrome
trisomy 13
what is epigenetics
study of how your behaviours and environment can cause changes that affect the way your genes work
what do epigenetics do to DNA
change the way that the body processes + reads a DNA sequence
what genetic modification already exists
embryonic screening + selection
what is embryonic screening + selection
technique which enables ‘faulty’ genes to be identified prior to implantation
what is the legal framework regarding genetic modification in the UK
genetic modification IS legal for medical reasons but not social or economic
what affects the microbiome
- diet
- lifestyle
- age
- sex
- environment
- medications
why is skin to skin considered more important for c/s births
because the maternal microbiome impacts fetal development.
what impacts the microbiome
- type of birth
- skin to skin
- mode of feeding
- other environmental factors
what does breastfeeding provide to help fetal gut
- bifidobacteria
- oligosaccharides
both help proliferate the gut with beneficial bacteria
what is ‘gut dybiosis’
an imbalance within the baby’s gut which can have a long-term impact on health and wellbeing
