DNA structure and function Flashcards
What are the three cell theories?
- All living things must have cells
- New cells come from pre-existing cells
- Cells are the smallest unit of life.
What are the two main types of cells?
Eukaryotic and prokaryotic
What is a prokaryotic cell? (5)
A bacteria cell.
- It is less complex
- No nucleus
- Unicellular
- No membrane bound organelles
What is a eukaryotic cell?
(5)
Animal/plant cell
- Complex
- Nucleus
- Multicellular
- Membrane bound organelles
What is a cell membrane
All cells have a cell membrane, it acts as a barrier around the cell
What is cytoplasm?
Fluid inside the cell membrane surrounding everything inside.
What is DNA?
Genetic information that gives instructions to make proteins for the body. It provides all necessary information to reproduce and construct a new organism.
What are Ribosomes?
This is where proteins are synthesised. It takes amino acids and make a genetic chain.
How is a trait determined?
Traits are determined by a special molecule called DNA.
What is the DNA structure?
DNA is arranged in a double helix.
It is made up of nucleotides.
What are nucleotides made up of?
Sugar phosphate backbone and four nucleotide bases.
What are genes?
Genes are sections of DNA.
Genes code for proteins that do various jobs around your body.
What do both eukaryotic and prokaryotic cells have in common?
- ribosomes
- Cell membrane
- DNA
- Cytoplasm
In what order does the body use amino acids as building blocks?
Amino acids
Proteins
Living cells
Tissue
Organs
How can we read the genetic code
When you look at half of the DNA molecule
How is RNA made?
Chemicals inside the nucleus make partial copies of the DNA code. This is called RNA.
What does RNA do?
They move from the nucleus to the cytoplasm to the ribosome, from here the ribosomes create proteins.
What is the structure of a chromosome?
The are rolled up strands of DNA
Most humans contain a full set of chromosomes how many pairs are there?
23 pairs of chromosomes are in every cell nucleus. With 22 pairs being autosomes and 1 pair being the sex chromosome.
What are the chromosomes for the female and male?
Males chromosomes are xy
Female chromosomes are xx
What is a mutation?
A mutation is a change in the DNA. This is usually random and can be a result of exposure to mitogens. Mutations are usually permanent. They can either be harmful of beneficial.
What causes mutations?
- Errors in the DNA system
- Cell division
- Mutagens
What is a spontaneous mutation?
Random mistakes in the normal process of a DNA replication.
What is an induced mutation?
A mutation caused by the environment. Such as the impact of radiation. For example the HPV virus increases the risk of cervical cancer.
What is the sugar in DNA called
Deoxyribose
What are the 4 nitrogenous bases of DNA
Cytosine
Guanine
Adenine
Thyme
What nitrogenous bases are complementary?
Adenine and Thyme
Cytosine and Guanine
What are Alleles
These are variations of a gene. They code for different versions of the same characteristics. these versions are known as traits.
What is a Genotype?
Genotypes are made up of ones allele.
They are traits that get passed to us through hereditary.
What is a phenotype?
Is physical traits that we can see. (bleached hair)
What does homozygous mean?
Both alleles are the same
What does heterozygous mean?
Two different alleles.
What is miosis?
Meiosis consists of 5 phases, that occur twice, to produce four haploid daughter cells
What happens to the cell during interphase
The cell grows and replicates its DNA
What happens to the cell during prophase I
Chromosomes condense and homologous pairs come together to form tetrads. Crossing over may occur, where segments of DNA are exchanged between homologous chromosomes.
What happens to the cell during metaphase I
Tetrads line up along the middle and spindle fibres attach
What happens to the cell during anaphase I
Homologous chromosomes separate & are pulled to opposite ends of the cell
What happens to the cell during Telophase I and Cytokinesis
The cell divides into two daughter cells, each with a diploid set of chromosomes.
What happens to the cell during prophase II
Chromosomes recondense and spindle fibres form
What does an egg and a sperm make?
Zygote
What does a chromosome do?
Chromosomes allow DNA to be accurately copied during these cell divisions.
What are gametes?
sex cells
