Biology exam

Prokaryotic vs Eukaryotic Cells 

Prokaryotes are simple cells with no nucleus, while eukaryotes are complex cells that keep their DNA inside a nucleus.

Plant vs Animal Cells 

Plant cells have a hard cell wall, a vaculor space, and chloroplasts for sunlight, while animal cells do not

Eukaryotic organelles - Name and function 

Mitochondria turn food into usable cell energy, and ribosomes build tiny proteins for the cell.

Structure and function of the plasma membrane 

A flexible outer skin made of fats and proteins that controls what goes in and out of the cell.

Passive vs Active Transport 

Passive transport moves things across the cell without using energy, while active transport uses energy to push things across.

Osmosis, simple diffusion, facilitated diffusion and active transport (the processes with examples) 

Osmosis moves water, simple diffusion moves small gases like oxygen, facilitated diffusion uses helper tunnels for bigger things, and active transport uses power to pump ions.

Molecules which can easily pass through the plasma membrane 

Tiny uncharged molecules like oxygen and carbon dioxide pass straight through the skin.

Autotrophs vs Heterotrophs 

Autotrophs make their own food using light, while heterotrophs must eat other living things for food.

Photosynthesis Why is it important? 

It makes food for plants and puts clean oxygen into the air for us to breathe.

Photosynthesis Worded equation 

Carbon dioxide + Water → Glucose + Oxygen

Photosynthesis Chemical equation

Aerobic Cellular Respiration What is it for/why is it important?

it breaks down food using oxygen to give the cell lots of usable energy.

Aerobic Cellular Respiration Worded equation

glucose + oxygen → carbon dioxide + water + energy release.

Aerobic Cellular Respiration Chemical equation

Anaerobic fermentation Outputs of animal and yeast fermentation 

Animal cells make lactic acid, while yeast cells make alcohol and carbon dioxide bubbles.

Difference between aerobic and anaerobic respiration/fermentation

Aerobic needs oxygen and makes lots of energy,while anaerobic works without oxygen and makes very little energy.

DNA structure 

A twisted ladder shape made of two connected strands of coded information.

Structure of a nucleotide 

A single building block made of a sugar, a phosphate group, and one letter base.

Chromosome structure and numbers within somatic and sex cells

Chromosomes are tightly packed DNA sticks, with full pairs in regular body cells and half counts in egg or sperm cells. somatic: 46. sex cells: 23 (sperm ovum)

Genotype vs phenotype 

Genotype is the secret gene code you inherit, while phenotype is the visible trait you can see.

Dominant vs recessive traits - including incomplete dominance and codominance 

Strong dominant genes cover weak recessive ones, incomplete dominance mixes traits together, and codominance shows both traits side by side.

Stages of the Eukaryotic cell cycle 

The cell grows, copies its DNA, divides its nucleus, and then splits completely in two.

Binary fission 

Simple bacteria splitting directly down the middle to copy themselves into two identical cells.

define what a Stage of meiosis is and explain the process

A special double cell division process that creates four unique egg or sperm cells.
·       Prophase I: Matching chromosomes pair up and swap DNA pieces to create unique combinations.

·       Metaphase I & Anaphase I: The chromosome pairs line up in the middle and pull apart.

·       Telophase I: The cell splits in half, forming two new cells with half the DNA.

·       Prophase II & Metaphase II: In both new cells, the chromosomes line up single-file down the center.

·       Anaphase II: The chromosome copies separate and move to opposite sides of the cells.

·       Telophase II & Cytokinesis: Both cells split, leaving four unique sperm or egg cells with 23 chromosomes each.

Events during meiosis which increase genetic diversity

Chromosomes swap tiny genetic pieces and line up randomly so every child looks different.

Pedigrees - autosomal recessive, autosomal dominant, X- linked recessive add dominant 

Family tree diagrams that track how a specific health condition or physical trait moves through generations.

Karyotypes

A picture of a person's full set of chromosomes lined up by size to check for missing or extra parts.

Definition of evolution and natural selection

Evolution is how living things slowly change over time, driven by survival of the fittest.

Definition of a species, and how species come to be

A species is a group of animals or plants that can breed together to make babies that can also have babies.

Speciation (isolation)

When a group gets trapped away from others for so long that they change and become a brand new species.

Homologous and analogous structures 

Homologous structures are body parts inherited from a shared ancestor, while analogous structures look similar because they do the same job.

Phylogenetic trees 

Branching family trees that show how different species are related to each other across history.

Consequences of the Cretaceous–Paleogene extinction

A giant space rock wiped out the non-flying dinosaurs, leaving room for mammals to spread and grow.