bio term 1 Flashcards
What does DNA stand for?
Deoxyribonucleic acid
What is the structure and shape of DNA?
Structure - Nucleotides (3 parts)
Shape - a double helix
Where is DNA found?
Contained in the nucleus
What are the 3 parts of a nucleotide?
Phosphate, sugar, base
What are the complementary base pairs?
Adenine and Thymine
Cytosine and Guanine
Define gene?
Segments of DNA in a chromosome.
What are chromosomes made of?
segments of DNA called genes
How many chromosomes are there in a human cell?
46 chromosomes (23 pairs)
What is the genetic code?
The order of bases of each gene contains information for one characteristic. this is known as the genetic code.
What are the two basic functions of DNA?
Carry genetic information for inheritance
Coding for amino acids to produce proteins
Define DNA replication
This is to carry the genetic code accurately and pass it on to future generations.
What are the steps in DNA replication?
- “unzip” the DNA strand
- Bases of exposed strands pair up with free nucleotides forming new complementary strand
- The new strand is identical to the first
What is protein synthesis?
The process of making proteins in the cell
How do proteins work?
- Amino acids link to form proteins.
- They are synthesized in the ribosomes.
- Must be copied to RNA which then goes through the nuclear pores.
- The ribosome reads the codon and signals for the correct acid to be added to the protein chain.
Where to we get amino acids from?
The food we eat
How many amino acids are there in total?
20
What are amino acids made up of?
1 codon
What is a codon?
3 bases combined
What does RNA stand for and what is it’s base pairs?
Ribonucleic acid.
Cytosine to guanine
Adenine to Uracil
Where is RNA formed?
In the nucleus and cytoplasm.
Define Alleles
Variety of a gene
Define Genotypes
Combination of alleles. They help to determine phenotype
Define ribosome
manufacture proteins
Define Phenotype
A physical characteristic based on genotype
Define Dominant trait
A trait that only requires a single allele to be expressed. (Capital letter)
Define Recessive trait
Only expressed if there are no alleles for the dominant trait present. (lowercase)
Define Heterozygous
The term used when the alleles are different. eg: Bb
Define Homozygous
The term used when the alleles are the same. Also known as ‘pure breeding’.
eg: BB
Define evolution
Is defined as the gradual change in a characteristic of a species over time
What does evolution occur through? and who discovered this process?
Natural selection
Charles Darwin and Alfred Wallace
Define natural selection?
A process by which a species becomes better adapted to it’s environment
What are two key inferences discovered from natural selection?
- In the struggle to survive, those individuals most suited to their environment survive
- Those individuals that survive pass on their traits to their children
What is transcription?
- Make a copy of gene as a strand of mRNA
- Strand leaves gene
What is translation?
- mRNA travels to ribosome
- tRNA bring the required amino acid to the ribosomes
- amino acids join to make protein
What is tRNA?
Transfer RNA used in translation
What is mRNA?
messenger RNA
define the nucleus
contains the DNA/genetic material and controls the many functions of the cell
Define nuclear pores
gaps in the nuclear membrane through which small molecules can pass (mRNA)
define nucleolus
Located in the nucleus and contains RNA (which can be used to make mRNA)
