biological foundations Flashcards
What is a gene
A segments of DNA along the length of the chromosome
What is the process where DNA duplicates itself called
mitosis
Genes influence human characteristics by:
Sending instructions for making proteins to the cytoplasm
What is cytoplasm
Areas surrounding the nucleus
What does crossing over refer to
In the gamete (sex cells) chromosomes next to each other great at one or more points along the length and exchange segments
Which process ensures siblings differ even though they come from the same genes
Meiosis
What effects the likelihood of identical twins occurring
Environmental influences, temperature changes, oxygen levels, late fertilisation of the ovum, genetic influence
Non-red hair is dominant. An individual with red hair has which type of allele
An homozygous allel for red hair
X-linked disorders are more commonly found in males than in females because ——–
When a harmful allel is carried on the X chromosome their is no chance of this being cancelled out by a more dominant gene on the other X chromosome as for women
What is the effect of ionising radiation on DNA
Can cause mutation
What is polygenic inheritance
Many genes determine the characteristic in question: height, weight, intelligence, personality.
When do chromosomal defects occur
During meiosis
What is one chromosomal abnormality
Down syndrome
What is the main effect of a sex chromosome disorder
Specific intellectual problems
Which is the safest form of prenatal diagnosis
Maternal blood analysis
By the fourth day after conception, the developing organism is/has:
Blastocyst is formed
What are the three phases of prenatal development
Zygote, embryo, fetus
During prenatal development in which period do the most rapid prenatal changes take place
The embryo
What is the term for an environmental agent that can cause damage in the prenatal period
Teratogen
During which trimester does the cerebral cortex, neural networks, and personality begins to emerge
Third trimester
Which common drugs can affect, low birth weight and death at time of birth, poorer motor development, lower intelligence test scores in early childhood.
Regular use of aspirin
The effects of fetal alcohol syndrome are reversible: true or false
False
What is the effect of taking folic acid supplements around the time of conception
Significantly reduces the risk of neural tube abnormality such as spina bifida
What does research on maternal age provide
Women in their 30s have the same risk of having babies with chromosomal abnormalities as women in their 20s thereafter complication rates increase with a sharp rise amongst women 50 to 55
