EOY Exam Essential Vocab Revision - Biology Flashcards
Cells
The smallest unit of lifeforms, building blocks of living things.
DNA
Deoxyribonucleic Acid
A substance found in all living organisms that contains genetic information.
Nucleus
Spherical structure inside a cell that contains DNA and acts as the control centre for the cell.
Gene
A specific segment of a DNA molecule. The base sequence of this gene for a specific protein product determines a specific characteristic of an organism
Linked Genes
Genes that are located on the same chromosome are described as linked genes
Chromosomes
Thread like miniscule structures inside the nucleus of a cell that contains DNA.
Centromere
The approximate central location of a chromosome, also the point where sister chromatids link together.
Chromatid
One identical replicated half of a duplicated chromosome, referred to as sister chromatids when talking about both chromatids.
Autosomes
Non-sex chromosomes
Sex Chromosomes
Chromosomes that determine the sex of an organism. X and Y are the two different types of sex chromosomes
Somatic Cells
Body cells excluding sex cells
Gametes
Sex cells (sperm, ova)
Gonads
Sex organs, where sex cells are produced and where meiosis occurs
Homologous
Refers to chromosomes that are matching pairs as they are similar in shape and size. Non-matching pairs of chromosomes are referred to as Non-homologous.
Karyotype
An x-ray like image of chromosomes that orders chromosomes based on their size.
Genetic Mutation
Where one less or one extra chromosome is duplicated.
Mitosis
Type of cell division that occurs in somatic cells when your body is going through growth, repairment or replacement. Mitosis results in the identical replication of it’s original cell with the same amount of chromosomes.
Meiosis
Type of cell division that occurs to produce gametes (ova (females reproductive cell) or sperm (male reproductive cell)). Meiosis results in the creation of 4 daughter cells, all unidentical to the original parent cell leading to genetic variety. Meiosis also results in the amount of chromosomes (46) being halved (23).
Parent Cell
The original cell that carries out the process of cell division.
Daughter Cell(s)
The cell that is produced after the parent cell goes through cell division.
Haploid
When a cell possesses one copy of each chromosome. Odd number of chromosomes.
Fertilisation
When the ovum is penetrated by sperm.
Zygote
When your mother’s 23 chromosomes are combined with your father’s 23 chromosomes to create a total of 46 chromosomes.
Nucleotides
DNA building blocks consisting of a phosphate part, sugar group and a nitrogen-containing base.
Sugar Group
Deoxyribose
The sugar found in nucleotides that make up DNA. Often drawn as a pentagon.
Phosphate Group
The phosphate group is found in nucleotides that make up DNA. Often drawn as a circle.
Base
Nitrogenous Base
A component found in nucleotides that make up DNA. Often drawn as rectangles There are four types of Bases, Adenine (A) and Thymine (T), and Guanine (G) and Cytosine (C).
Complementary Base Pairs
Refers to the pairs of bases that match up, for example A and T are complementary base pairs and C and G are complementary base pairs
Double Helix
The shape used to describe DNA. Helix refers to a curving-spiral like shape.
Genome
The complete set of genes present in a cell or organism.
Diploid Number
The number of chromosomes in somatic cells. Diploid refers to when there are 2 copies of each chromosome in a cell, so a diploid number is the number of 2 copies of chromosomes in a cell. Diploid number is identified as 2n. Even number.
Haploid Number
The number of chromosomes in a gamete. Haploid refers to when there is only 1 copy of each chromosome in a cell, so a haploid number is the number of chromosomes that are singular in a cell. Haploid number is identified as n. Odd Number.
Phenotype
The characteristics that are developed in an individual which are influenced by environment and genotype. These characteristics can be seen or are displayed.
Genotype
The set of genes carried by and individual which are inherited from an individual’s parents.
Homozygous Alleles
Both chromosomes in the pair carry the same version of the gene.
Heterozygous Alleles
Both chromosomes in the pair carry a different version of the gene.
I+PMAT
Interphase + Prophase, Metaphase, Anaphase, Telophase
Number of chromosomes in humans
46 chromosomes, 23 pairs
Number of chromosomes in sex cells
23 chromosomes
Down Syndrome
Extra 21st chromosome caused by mutation
Hydrogen Bonding
Found between the two strands of DNA that connects the “rungs of the ladder”
Complete Dominance
The dominant allele entirely masks the recessive allele and 1 trait is shown
Incomplete Dominance
Both Traits are combined before a fusion is expressed. Example is curly hair and straight hair resulting in wavy hair.
Co-dominance
When two traits are each distinctively expressed. Such as a balck cow and white cow giving birth to a black and white cow.
Polymer and Monomers in DNA
A nucleotide is a monomer (a building block) and the DNA is a polymer chain (multiple monomers connected)
Reading DNA Code
DNA code is read in three bases at a time
Sexual Reproduction and cell division
Organisms that sexually reproduce undergo meiosis.
Interphase
The phase the cell spends the most time doing. During interphase, DNA is not coiled up into chromosomes but rather free floating and not visible. During interphase, cell duplicates DNA and organelles.
Organelles
Components found inside a cell (example: cell wall, nucleus, mitochondria, etc)
Prophase
Both in Meiosis and Mitosis
Chromosomes become visible and thicken up as they condense
Metaphase - Mitosis
Chromosomes line up in a single file line in the middle (m for middle)
Metaphase - Meiosis Stage I and II
Stage I = Chromosomes line up in a paired line in the midle
Stage II = Chromosomes line up in a single-file line in the middle
Anaphase - Mitosis
Chromatids are oulled away to opposite sides of the cell by spindles
Anaphase - Meiosis Stage I & II
Stage I = Chromosomes are pulled away to opposite sides of the cell
Stage II = Chromatids are pulled away to the opposite sides of the cell
Telophase
Both Mitosis and Meiosis
Nucleuses start to form around the divided cell
Cytokinesis
Occurs when the cells split apart. Cytoplasm splits away.
End of Mitosis results in 2 identical daughter cells
End of Meiosis results in 4 unidentical daughter cells and will have half the number of chromosomes
Non-disjunction
Anaphase doesn’t occur smoothly, chromosomes/chromatids don’t split properly and genetic mutation occurs
Dominant vs Recessive Gene
Dominant Genes (often written as capital lettrs) mask recessive genes, leading to the dominat trait being expressed. Recessive genes (often written as lowercase letters) get masked by dominant genese and can only be expressed if both genes are recessive. Recessive traits can skip generations.
Pedigree Charts
Display patterns of inheritance
Sufferer
When a person/organsim displays the certain recessive traits
Carrier
When a person carriers a recessive diseased/specific trait, but doesn’t display it as it is masked by a dominat trait
Purebred
Homozygous genotype. Can be homozygous dominant (both dominant alleles) or homozygous recessive (both recessive alleles)
Inheritance
Genetic Transmission of characteristics from parents to offspring
Heterozygous genotype
Carrying a different set of alleles (one dominant, one recessive)
Selective Breeding
When the parents of an offsring are purposefully chosen to ensure the offspring carries a desired trait. Such as purposefully breeding red and white flowers to get a pink flower.
