BIO - MOD 7 (INFECTIOUS DISEASES)

what is sexual reproduction?

process where two parents combine genetic material to produce offspring that are genetically unique

what is asexual reproduction?

a single parent produces offspring that are genetically identical to itself, without fusion of gametes

what is fertilisation?

the fusion of male and female gametes to form a zygote

what does heterotrophic mean?

an organism that gets nutrients and energy by consuming other organisms or organic matter

what does autotrophic mean?

an organism that can produce its own food from simple inorganic substances like CO2 and water

what are prokaryotes?

single-celled organisms that lack a nucleus and other membrane-bound organelles

what are eukaryotes?

organisms whose cells contain a nucleus and membrane-bound organelles

what is binary fission?

asexual reproduction in prokaryotes where a parent cell duplicates its DNA and splits into two identical daughter cells

what is budding?

a type of asexual reproduction where a new organism grows as an outgrowth from the parent

what is implantation?

when a fertilised egg attaches to and embeds in the uterus lining, marking the start of pregnancy

what is ovulation?

the rupture of the dominant follicle in the ovary, releasing an egg for fertilisation

what is pregnancy?

the state where a fertilised egg implants in the uterus and develops into an embryo, then a fetus

what is DNA replication?

the process of copying one DNA molecule into two identical DNA molecules before cell division

what is mitosis?

cell division that produces two genetically identical daughter cells

what is meiosis?

cell division that halves the chromosome number to make haploid gametes

what is a nucleotide?

the building block of DNA/RNA, made of a phosphate group, a sugar, and a nitrogenous base

what is transcription?

copying a gene's DNA sequence into mRNA, which happens in the nucleus

what is translation?

a ribosome reading mRNA to build a chain of amino acids (polypeptide)

what is a gene?

a segment of DNA that codes for a specific trait by giving instructions to make a protein

what is a codon?

a sequence of three nucleotides on DNA/RNA that codes for an amino acid or signals start/stop

what is an anticodon?

a three-base sequence on tRNA that is complementary to a codon on mRNA

what is mRNA?

a single-stranded RNA molecule that carries genetic information from DNA to the ribosome

what is tRNA?

a small RNA molecule that carries a specific amino acid to the ribosome, matching its anticodon to an mRNA codon

what is a ribosome?

the organelle responsible for protein synthesis (translation)

what is a polypeptide?

a chain of amino acids linked together by peptide bonds

what is a protein?

a molecule made of one or more polypeptide chains, used for structure, function and regulation

what is genotype?

the complete set of genes an organism has; its genetic blueprint

what is phenotype?

the observable characteristics of an organism, resulting from genotype and environment interacting

what are autosomes?

the numbered chromosomes (not sex chromosomes); humans have 22 pairs

what is an allele?

an alternative form of a gene found at the same location on homologous chromosomes

what is artificial insemination?

assisted transfer of sperm into a female's reproductive tract without mating

what is artificial pollination?

manually transferring pollen from the male part of a plant to the female part

what is biodiversity?

the variety of living organisms within a habitat, ecosystem or globally

what is genetic variation?

the differences in DNA among individuals of the same species, creating a variety of traits

what hormone does the corpus luteum produce?

progesterone

what hormones does the pituitary gland produce (in reproduction)?

follicle-stimulating hormone (FSH) and luteinising hormone (LH)

what are examples of fungi?

yeast, mould and mushrooms

how do fungi reproduce?

asexually, through budding or spores

what are protists?

eukaryotes that are not fungi, plants or animals; they belong to their own kingdom

how do bacteria reproduce?

by binary fission

what does luteinising hormone (LH) do?

triggers ovulation, causing the mature follicle to rupture and release an egg

what produces oestrogen?

developing follicles in the ovary, stimulated by FSH

what is the role of oestrogen?

rebuilds and thickens the endometrium, prepares the body for pregnancy, and stimulates placenta growth

what is the role of progesterone?

prepares and maintains the endometrium, prevents contractions, and supports the developing placenta

what structures produce progesterone?

the corpus luteum first, then later the placenta

what does human chorionic gonadotropin (hCG) do?

keeps the corpus luteum alive so it keeps producing progesterone (and some oestrogen) to maintain the pregnancy

what are the three stages of sexual reproduction in flowering plants?

pollination, fertilisation and seed dispersal

what other hormones are involved in human pregnancy?

cortisol (matures baby's lungs), relaxin (loosens pelvis), and prolactin (stimulates milk production)

what is selective breeding?

humans choose which individuals breed to produce offspring with desired traits

what is genetic engineering?

altering an organism's DNA, usually by cutting a gene from one organism and inserting it into another

what is cloning?

producing genetically identical organisms, e.g. through plant cuttings or embryo splitting

what is hybridisation?

breeding organisms together to blend their traits

what cells does mitosis occur in?

all cells in a multicellular organism, except sex and germ cells

what are the phases of mitosis?

prophase, metaphase, anaphase and telophase

what cells does meiosis occur in?

sex cells (germ cells)

what is DNA made of?

nucleotides

where is DNA found?

the nucleus

what is a nucleotide made of?

a phosphate, a sugar, and a nitrogenous base

which nitrogen bases pair together?

adenine with thymine, and guanine with cytosine

what type of protein carries out DNA replication?

enzymes

what are the steps of DNA replication?

the double helix unwinds, primase makes a starting point, new nucleotides pair up (A-T, G-C), DNA polymerase builds the new strand, and DNA ligase joins the fragments together

why is meiosis important for a species?

it makes gametes for fertilisation, allows reproduction to continue, and creates genetic diversity

why is mitosis important for a species?

it allows growth and repair, and ensures each new cell has a full set of chromosomes

what are the two stages of protein synthesis?

transcription and translation

what are the steps of transcription?

RNA polymerase separates the DNA strands, free nucleotides pair up (G-C, A-U) to form mRNA, introns are edited out, then mRNA moves to a ribosome

what are the steps of translation?

tRNA brings amino acids that match the mRNA codons, and these amino acids join together to form a polypeptide/protein

how does the environment affect phenotype?

e.g. temperature changes fur colour in Himalayan rabbits, and sun exposure increases melanin in human skin

what are the four levels of protein structure?

primary, secondary, tertiary and quaternary

what are the main types of proteins?

enzymes, structural, transport, contractile, regulatory, and storage/protection proteins

what do enzymes do, and what is an example?

speed up biological reactions, e.g. catalase breaks down hydrogen peroxide

what do structural proteins do, and what is an example?

provide strength and structure, e.g. keratin in hair and wool

what do transport proteins do, and what is an example?

carry substances around the body, e.g. haemoglobin transports oxygen in the blood

what is homozygous?

having two of the same allele for a gene, e.g. TT or tt

what is heterozygous?

having two different alleles for a gene, e.g. Tt

what processes make up cell replication?

mitosis and meiosis

what processes make up protein synthesis?

transcription and translation

what must happen before cell replication?

DNA replication

what are the stages of the cell cycle?

interphase (growth, DNA replication) and mitosis (prophase, metaphase, anaphase, telophase)