TOPIC 4: GENETIC & EVOLUTIONARY INFLUENCES ON BEHAVIOUR Flashcards Preview

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Flashcards in TOPIC 4: GENETIC & EVOLUTIONARY INFLUENCES ON BEHAVIOUR Deck (84)
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1

DNA

- Deoxyribonucleic acid (DNA)

- Double helix joined by nucleotides

- Nucleotides are
(A adenine)<=>(T thymine)
(G guanine)<=>(C cytosine)

2

Genes

- Made up of DNA segments

- Guide synthesis of proteins which form/alter physiologic systems, via RNA (ribonucleic acid)

3

Chromosomes

- Structures in cell nucleus

- Comprised of 23,000 genes

- 23 pairs = 46 chromosomes

- 50% of chromosomes inherited from each parent, randomly selected.

4

Alleles

Pair of genes occupying the same locus on a pair of chromosomes

5

Gregor Mendel (1865)

Cross bred peas to make hybrids

- Two original purebred strains, differing in one trait, one was round the other was wrinkled

6

F1 and F2 of Mendel's pea breeding

F1 : resulted in Rr(round) and Rr(round)

F2 : resulted in RR(round), Rr(round), Rr(round), rr(wrinkled)

7

Phenylketonuria (PKU)

- Can cause reduced head and brain size, motor coordination problems, intellectual disabilities and physiological disorders.

- effects 10 per 100,000

- caused by an enzyme that produces a enzyme that ineffectively metabolizes amino acid phenylalanine

- Allel is recessive

8

Where is phenylalanine found

found in some high protein foods, components of aspartame.

9

Environmental treatment for genetic defect (Phenylketonuria)

avoid phenylalanine

10

Polygenic

A trait cannot be accounted for by a single gene and is continuous rather than discrete.
(non-Mendelian)

11

The goal of epigenetics

The goal of epigenetics is to explain how the environment interacts with genetic information In the body.

12

why and how is protein translated.

Because almost every body cell has a copy of DNA, it has the capability of expressing a gene, by being transcribed into molecules of RNA, which are then translated into protein.

13

True or False - every gene in any cell is active

FALSE : Only 10-20% of genes are active in any cell.

14

What does Epigenetics guide?

They guide proper development of stem cells into different specialized cells of the body.

15

What is Epigenetics the study of?

Epigenetics is the study of changes in the regulation of gene activity and expression that are not dependent on gene DNA sequence.

16

Epigenomic Mechanisms

Control of gene expression can occur in different ways

- DNA methylation

- Histone modifications

17

DNA methylation

- Molecules called methyl groups attach to DNA

- This effects what gets translated into RNA and proteins, preventing gene expression.

- Methyl groups are present in foods, household chemicals, and environmental pollutants

18

Histone modification

- DNA is wrapped around protein structures called histones, like thread around a spool.

- some chemical groups attach directly to histones, loosing or tightening their connection to DNA, turning genes off or on.

19

How do experiences influence the epigenome ?

Certain antidepressants have been found to reverse both genetic and behavioural effects

20

How does genetic risk combine with experience and environment to produce identical twins?

- if one of the twins is autistic, there is a 60% the other is too.
- schizophrenia = 50%
- bipolar disorder = 75%

21

How do psychoactive drugs rewrite the epigenetic code?

- Addictions maybe cured--or even prevented-- by interrupting or reversing epigenetic changes. This can alter some genes temporarily, other more permanently.

22

Can epigenetic information be inherited?

Your experiences may actually cause changes In gene regulation that are passed on to your offspring.

23

Charles Darwin

- around world Galapagos visit and compared finches and adaptions

- compared present day creatures to fossil record

- wrote On the origin of species, which included evolutionary biology.

24

what were the 4 premises of On the origin of species.

1) life is dynamic: species change with time

2) evolution is gradual and continuous (sudden environmental changes ==> some species die out)

3) stats quo maintained in a static environment

4) all current organisms descended from an original ancestor

25

the 2 mechanisms

natural selection and artificial selection

26

natural selection

selective breeding by nature

27

Spencer (1864)

"survival of the fittest" : means suitability or match with the environment, not physical strength.

28

artificial selection

selective breeding by human action.

- individuals with desired traits encouraged by human action.

- pass on their genetics or characteristics.

29

how does genetic change occur

through two ways:
sexual reproduction and mutation

30

sexual reproduction

"shuffles the deck" of genes from parents