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Biology > Biology Definitions > Flashcards

Biology Definitions Flashcards

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AP® Biology flashcards Biology 101 flashcards
0
Q

Genotype

A

A statement of the genes a person has for a characteristic

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1
Q

Phenotype

A

A statement of the physical appearance of the person for that characteristic

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2
Q

Homozygous

A

Where both of the chromosomes carry the same allele e.g. TT or tt

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3
Q

Heterozygous

A

Where the chromosomes each carry a different alleles for that characteristic e.g. Tt

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4
Q

Autosomal

A

Not sex linked. Genes on chromosomes that don’t determine sex ie. same for males and females

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5
Q

X – linked

A

Sex linked. Genes that change depending on the sex of the organism. They are found on the X and Y chromosome’s

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6
Q

Gene

A

The basic functional unit of a DNA molecule that contributes to the inheritance of characteristics

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7
Q

Chromosome

A

A strand of DNA and associated proteins. It contains genes at different loci.

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8
Q

Loci

A

The position of a gene on a chromosome

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9
Q

Allele

A

The alternative forms of genes that occupy the same locus on homologous chromosomes. They are expressed as different forms of the same characteristic.

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10
Q

Homologous chromosome

A

Members of a pair of chromosomes of similar structure, containing genes at the same loci, which pair during meiosis

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11
Q

Haploid

A

The number of chromosomes found in a gamete (n). This is half the number found in an ordinary body cell. Haploid cells are found in the ovary and testes. (Humans = 23)

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12
Q

Diploid

A

The number of chromosomes found in an ordinary body cell (or somatic cell). Found all over body.

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13
Q

Dominance

A

If one gene masks the effect of another. It is written with a capital letter

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14
Q

Recessive

A

A gene that is masked. It is written with a lowercase letter.

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15
Q

Crossing over

A

Crossing over will occur between the two in a chromatids of a pair of homologous chromosomes during meiosis and allows an exchange of genetic material from the mother and father.

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16
Q

Mutation

A

A spontaneous, random change to a gene, many genes or a whole chromosome. If the mutation is in a somatic (normal) body cell, it will affect the organism but not be passed on but if it is in a sex cell it will be inherited by the offspring.

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17
Q

Recombinant DNA

A

rDNA or recombinant DNA is a form of artificial DNA that is created by combining two or more sequences that would not normally occur. E.g. bacteria that makes insulin, BT cotton, hep B

18
Q

DNA

A

Deoxyribonucleic acid

Double-stranded helix, located in nucleus, chloroplasts and mitochondria.

Nucleosome (wrapped DNA) histone complex

Cell division – chromatin condenses into chromosomes so DNA can be transported to daughter cells

Arrangement in prokaryote’s – in circular ring, not coiled, also have smaller rings of DNA called plasmids

19
Q

Prokaryote’s

A

Single celled organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelles.

20
Q

Eukaryote

A

Membrane bound organelles

21
Q

Natural selection

A

The mechanism by which evolutionary change on earth has occurred.

22
Q

Mutations

A

A sudden, permanent change in a gene (gene mutation) many genes or a whole chromosome (chromosome mutation) and may introduce variation into the population.

23
Q

Somatic mutation

A

Occurs in a somatic (normal) body cell. It will affect the organism but not the offspring. E.g. not passed on.

24
Q

Sex Cell mutation

A

Occurs in sex cells. It will affect the offspring e.g. passed on/inheritable trait.

25
Q

Competition

A

Life is an ongoing struggle for survival so organisms compete for food, water, mates, sunlight, space and other resources in order to survive. If they cannot compete successfully then their chance of survival is slim and they won’t pass on their genes to future generations.

26
Q

Survival of the fittest

A

“Fitness” (the reproductive success and survival of individuals within species) Within species variation exist and since resources are limited, competition also exist. Individuals who compete successfully for resources are more likely to pass on the favourable characteristics to the offspring.

27
Q

“Fitness”

A

the reproductive success and survival of individuals within species

28
Q

Adaptation

A

Characteristics which best suit an organism to their environment. Those with favourable adaptations pass on genetics to the next generation, those with unfavourable characteristics will die and not pass on genes so the next generation will be better adapted.

29
Q

Selective pressures

A

Environmental factors which may reduce reproductive success in a population therefore contribute to ebullition airy change for extinction through the process of natural selection. E.g. competition, predation, disease, parasitism, land clearance, climate change, pollutants

30
Q

DNA profiling

A

Where are specific DNA pattern, called a profile, is obtained from the person or sample of bodily tissue.
A process that is able to identify natural variations that exist within an individual’s genome, by using the polymerase chain reaction and gel electrophoresis.

31
Q

Polymorphic

A

Pieces of DNA that very highly between individuals of the same species

32
Q

Polymorphisms

A

Differences in variable regions of DNA

33
Q

Short tandem repeats (STR’s)

A

A type of polymorphism. A region of non-coding DNA that contains repeats of the same nucleotide sequences. STR’s are found at different places/genetic loci in a person’s DNA.

34
Q

Transgenic organism

A

One whose genome has been altered by adding genes from a different species into it’s genome using recombinant DNA technology.

35
Q

Genetically modified organism

A

One whose genome has been modified or altered by gene manipulation and biotechnology, in particular recombinant DNA technology, to give it characteristics it does not have naturally.

36
Q

Codon

A

Series of three adjacent nucleotide bases in messenger RNA; each codon specifies a particular amino acid to be added to a polypeptide; stop codon indicates the termination of the polypeptide chain.

37
Q

DNA ligase

A

An enzyme used to catalyse the formation of a bond between two pieces of DNA.

38
Q

DNA polymerase

A

An enzyme capable of making exact copies of fragments of DNA

39
Q

DNA sequencing

A

A process of establishing the nucleotide sequence of a piece of DNA

40
Q

DNA Helicase

A

An enzyme that helps the two strands of the DNA double helix unwind and separate

41
Q

DNA fingerprinting

A

Also called DNA profiling; based on patterns of non-coding, repeating bass sequences in the genome.

42
Q

Genetic code

A

The system by which each combination of three DNA nucleotides in a gene sequence determines specific amino acid in a protein.

Biology (13 decks)

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