Yr10 Science; Biology - Genetics and inheritence

What is an IV

variable that changes

What is a DV

variable that is measured

What is a CV

variable that stays the same

define homozygous

a genotype with the same alleles

define heterozygous

a genotype with different alleles

define genotype

a pair of alleles that influence the appearance of a particular trait

define phenotype

an organism's collection of observable traits

define alleles

different versions of a gene

for dominant genes, how many copies of an allele is needed?

one copy

define simple inheritance

the appearance or absence of a trait is controlled by a single gene

recessive traits are hidden when…

the dominant allele is present

order of DNA

cell -> nucleus -> chromosones -> DNA -> Genes -> base pairs (G,T,A,C)

define DNA

a molecule that contains genetic information

define double helix

The structure of DNA which consists of two chains twisted around each other

define amino acid

A small molecule that joins with others to form proteins

define base pairing rule

Two bases that join together

define replicate

A repeat of an experiment

define gene

A unit of genetic information - code for proteins

define RNA

a single stranded nucleic acid, similar to DNA, plays a crucial role in various biological processes

define chromosome

threadlike structures made of DNA molecules that contain genes

define chomatin

mixture of protein and DNA

define chromatid

one of the two identical strands of DNA that make up a replicated chromosome

define adenine

base that combines with thymine to form a base pair

define thymine

the base that combines with adine to form a base pair

define cytosine

base that combines with guanine to form a base pair

define guanine

base that combines with cytosine to form a base pair

what are the parts of the structure of the double helix molecule in DNA?

sugar phosphate backbone, nitrogen bases (A-T, G-C), hydrogen bonds

what is complementary base pairing?

the way nitrogen bases pair up

A-T

G-C

what is the relationship between DNA, genes and chromosomes?

Chromosomes are made of DNA, and genes are specific sections of that DNA.

DNA → forms chromosomes → contains genes.

How does RNA enable protein synthesis in the ribsomes?

RNA enables protein synthesis by carrying the genetic code from DNA to ribosomes (mRNA), bringing the correct amino acids to match the code (tRNA), and helping the ribosome link them together into a protein (rRNA).

define homologous pair

A pair of chromosomes that have the same genes in the same order - one chromosome is inherited from each parent

define mutations

A change in the DNA sequence

define spindle fibre

Spindle Fibres (extended by centrioles) pull the chromosomes at the centrmetre, towards the poles

define mitosis

cell division for growth and repair

define meiosis

cell division for the production of sex cells

define interphase

stage of cell cycle in which a cell grows and copies its DNA

define prophase

the cell prepares for division - the chromosomes condense and the nucleus starts to break down

define metaphase

the chromosomes line up along the middle of the cell

define anaphase

the chromosomes separate and are dragged away from each other

define telophase

two nuclei form, each with its own set of identical DNA

define daughter cell

two cells that the initial (parent) cell has divided into - two new cells

define diploid

full set of chromosomes (23 pairs)

define haploid

half the set of DNA - single set of unpaired chromosomes

how is DNA copied in the cells by replication?

DNA replication produces two identical DNA molecules, each with one old strand and one new strand, using complementary base pairing and enzymes.

explain mitosis

The purpose of mitosis is to create diploid (two) daughter cells, with the same number of chromosomes as the original cell. This is how the body grows and repairs itself, including cells.

what is the relationship between the chromosome number and this process

mitosis keeps the chromosome number the same in new cells

define dominant allele

a version of a gene that is expressed even when only one copy is present

define dominant trait

A feature that appears when at least one allele is present

define recessive allele

a version of a gene that is only expressed when two copies are present - lowercase letters

define recessive trait

a feature that only appears when two alleles are present

define autosome

any chromosome that is not a sex chromosome

how many chromosome pairs are there in a human cell

22 autosome pairs (44)

1 sex chromosome (2/XX or XY)

define sex chromosome

a chromosome that determines an organism's gender

XX - female

XY - male

define gametes

reproductive cells

why is a controlled variable important in an experiment?

they keep the experiment fair and results valid

what is continuous data?

data that can take any value - eg: height

what is discrete data?

information that can only take certain values - eg: colour

when should a bar graph be used?

discrete data

when should a line graph be used?

continuous data

why do mutations occur?

Results from errors in DNA replication or from damaging effects of mutagens like radiation

4 stages of mitosis acronym

PMAT