Unit 1 Flashcards Preview

SQA Higher Biology > Unit 1 > Flashcards

Flashcards in Unit 1 Deck (59):
1

Chloroplast

The photosynthetic unit of a plant cell, contains all the chlorophyll

2

Induced pluripotent stem cells

Somatic (adult) stem cells reprogrammed to enter an embryonic stem cell-like state

3

Mitosis

Nuclear division

4

Natural selection

The survival of the fittest, whereby only individuals with the most suitable genetic constitution for any set of circumstances pass their genes on. The frequency of an allele increases in a population if it provides a selective advantage.

5

Pluripotent stem cells

These are stem cells, with the potential to make any differentiated cell in the body

6

Bioinformatics

A process which combines computer science and statistical analysis to study genomes

7

Gene pool

Complete set of unique alleles in a species/population

8

Allele frequency

The prevalence of alternative versions of genes

9

Allele

One of the different forms of a gene

10

Mutation

Creates many alleles for one gene pool

11

Gene migration

The movement of alleles between populations by individuals arriving from a different population and breeding. These individuals have a different gene pool and therefore introduce new alleles into the population.

12

Genetic drift

Tends to occur in small populations and describes the change in allele frequency due to a chance event. Small populations that are isolated from each other can vary greatly due to changes in allele frequency.

13

Non-random mating

Does not change the frequency of alleles, but increases the number of homozygous individuals. Interbreeding is the most common form.

14

Chance

Changes to allele frequency due to random loss (individual may die/fail to reproduce before death resulting in an allele being lost)

15

Sexual selection

The non-random increase in frequency of DNA sequences that increase reproduction

16

Stabilising selection

The average phenotype is selected and the extremes don't survive as well/may disappear

17

Disruptive selection

The extreme values of a phenotype survive

18

Directional selection

Only one extreme phenotype is selected over both the average and the opposite extreme

19

Speciation

The formation of a new species

20

Species

Group of organisms which can interbreed to produce fertile, viable offspring

21

Double helix

The double helical shape of a DNA molecule

22

Antiparallel

Running in opposite directions

23

Prokaryotes

An organism which lacks a membrane-bound nucleus

24

Eukaryotes

An organism which possesses a membrane-bound nucleus

25

Plasmids

A circular, self-replicating DNA molecule that carrie only a few genes

26

DNA ligase

An enzyme that facilitates the process by which fragments of DNA are joined together

27

Primers

A strand of nucleic acid that serves as a starting point for DNA

28

Leading strand

The strand of DNA that is being repeated continuously

29

Lagging strand

The strand of DNA that grows in the direction opposite to the movement of the growing fork. It is replicated in fragments

30

In vitro

Out with a living organism

31

In vivo

Within a living organism

32

DNA polymerase

An enzyme that synthesises DNA strands from individual nucleotides

33

Insertion

The addition of an extra nucleotide
Gene/point mutation

34

Deletion - gene

Loss of a section of DNA/number of nucleotides
Gene/point mutation

35

Translocation

Transposition of a length of DNA onto another chromosome
Chromosome structure mutation

36

Deletion - chromosome

Removal of a length of DNA from a chromosome

37

Duplication

Repetition of a series of nucleotides within a chromosome
Chromosome structure mutation

38

Inversion

The inversion/reversal of a section of DNA within a chromosome
Chromosome structure mutation

39

Substitution

The replacement of one nucleotide by another
Gene mutation

40

Genome

The entirety of an organism's hereditary information

41

Genomics

The science of interpreting genes. The study of an organism's genome using information systems/databases/computerised research tools

42

Genetics

The branch of biology that deals with hereditary, especially the mechanisms of hereditary transmission and the variation of inherited traits among similar or related organisms

43

Plastome

The genetic material that is found in plasmids in plant cells (e.g. in chloroplasts). It composes part of the entire genome of photosynthetic organisms.

44

Meristem

A growing point in a plant. Location of mitosis producing new cells.

45

Apical meristem

Growing points/regions of mitosis found at the tips of plant stems or roots allowing increase in length

46

Self-renewal

A property displayed by stem cells which allows them to produce more stem cells

47

Blastocyst

An embryo that has developed for 5-6 days after fertilisation

48

Differentiation

The process by which cells or tissues undergo a change towards a more specialised function.

49

Transcription

The production of mRNA from a DNA template

50

Intron

Part of the initial mRNA that is removed before translation

51

Exon

Part of the initial mRNA which is used to code for protiens

52

Translation

The sequencing of amino acids at ribosomes, based on the sequence of nucleotides in mRNA

53

mRNA/messenger RNA

Synthesised from a DNA template, resulting in the transfer of genetic information from the DNA molecule to the messenger RNA

54

tRNA/transfer RNA

A short strand of RNA that is twisted in on itself to expose 3 bases. Carries a specific amino acid to a ribosome.

55

rRNA/ribosomal RNA

The RNA that is a permanent structural part of a ribosome

56

RNA splicing

A process which removes the introns from a primary RNA transcript

57

Anticodon

A triplet of exposed bases on a tRNA molecule

58

Codon

A triplet of exposed bases on a length of mRNA

59

Ribosomes

Structures found in the cytoplasm where protein synthesis occurs.