Biology AS Level, OCR
- ANSWER Alpha glucose?
- ANSWER Amino acid?
- ANSWER ATP?
- ANSWER Beta glucose?
- ANSWER Dexoyribose?
- ANSWER Fructose?
- ANSWER Nucleotide?
- ANSWER Phospholipid?
- ANSWER Purine?
- ANSWER Pyrimidine?
- ANSWER Ribose?
- ANSWER Sterol?
- ANSWER Structure of a fatty acid?
- ANSWER Triglyceride?
- ANSWER tRNA?
- A cleavage furrow forms around the middle of the cell and the cytoskeleton pulls the membrane
inwards.
- In plants, a cleavage furrow cannot form as they have a cell wall. Instead, vesicles align on the
metaphase plate, and fuse to the cell surface membrane, dividing the cell into two. -
ANSWER What happens during Cytokinesis?
- Centromeres divide, separating the chromatids as the spindle fibres shorten. -
ANSWER What happens during Anaphase in mitosis?
- Chromatin fibres coil and condense to form chromosomes.
- The nuclear envelope disintegrates.
- Spindle fibres form at either pole of the cell. - ANSWER What happens during Prophase in
mitosis?
- Chromosomes are moved by spindle fibres to form a plane along the equator of the cell. This is
known as the metaphase plate. - ANSWER What happens during Metaphase in mitosis?
- Chromosomes condense and become visisble again.
- In each cell, the nuclear envelope breaks down and spindle formation begins. -
ANSWER What happens during Prophase 2 in Meiosis 2?
,Biology AS Level, OCR
- Contain myofibrils (which contain contractile proteins) to enable the tissue to contract and move
the bone. - ANSWER How is muscle tissue adapted to its function of enabling bones to
move?
- Embryonic stem cells present at a very early stage of embryo development and are totipotent.
- Tissue (adult) stem cells are present through life from birth. They are found in bone marrow and are
multipotent, though it may be possible to trigger them to become pluripotent.
- Umbilical cords of newborn babies. - ANSWER Sources of animal stem cells?
- Flexible, due to well-developed microfilaments and microtubules in the cytoskeleton.
- Many lysosomes, containing enzymes for hydrolysis of pathogens.
- Many ribosomes/RER to make enzymes.
- Many mitochondria for ATP
- Many Golgi for production of lysosomes.
-Multi-lobed nucleus to help cell squeeze through small gaps. - ANSWER How are
neutrophils adapted to their function of defending the body against disease?
- Heart disease: heart attacks can cause permanent damage to muscle tissue in the heart.
- Type 1 Diabetes: stem cells may enable body to produce its own insulin-producing cells which are
not attacked by the immune system.
- Parkinson's: symptoms caused by death of dopamine-producing cells, so stem cells could help this.
- Alzheimer's: stem cells used to repair brain cells.
- Spinal injuries: Stem cell implants could help to repair damaged spinal cords. -
ANSWER Uses of stem cells in the future.
- Homologous pairs of chromosomes pair up along the metaphase plate.
- The orientation of each homologous pair is random and so this leads to independent assortment, as
any alleles can be made facing the poles. - ANSWER What happens during Metaphase 1 in
Meiosis 1?
- In both cells, the chromatids of the individual chromosomes are pulled to opposite poles after
division of the centromeres. - ANSWER What happens during Anaphase 2 in Meiosis 2?
- Individual chromosomes assemble on the metaphase plate in each cell.
- Due to crossing over, the chromatids are no longer identical so there is more independent
assortment happening here. - ANSWER What happens during Metaphase 2 in Meiosis 2?
- It contains fibres of elastin and collagen, which increases its flexibility.
- It is firm and composed of chondrocyte cells, which makes it appropriate for use between bones. -
ANSWER How is the tissue cartilage adapted to its function?
- It is composed of columns of sieve tube cells and parenchyma cells (used for food storage).
, Biology AS Level, OCR
- Sieve plates separate the cells, and the perforations allow food to flow quickly.
- Has many mitochondria as it is required to use active transport. - ANSWER How is the
phloem tissue adapted for its function in the transportation of organic nutrients through a plant?
- It is composed of vessel elements, which are long and thin dead cells.
- They contain lingin to strengthen and waterproof these dead cells, providing structural support. -
ANSWER How is the xylem tissue adapted for its function in the transportation of water
and minerals through a plant?
- It is formed of closely packed cells.
- It is usually covered by a waxy cuticle to reduce the loss of water.
- It contains stomata to allow gas exchange. - ANSWER How is the epidermis tissue adapted
to its function in plants?
- Large SA:V ratio for maximum oxygen uptake.
- Very small so can fit through capillaries.
- No nucleus/ organelles, so more room for haemoglobin.
- Highly flexible, to fit through narrower capillaries. - ANSWER How are erythrocytes
adapted to their function?
- Many mobile chloroplasts to absorb light energy and provide ATP.
- They are long and thin and form a continuous layer on the surface of the leaf so that light can reach
them.
- Large vacuole pushes chloroplasts to the edges of the cell.
- Thin cell wall increases the rate of diffusion of CO2. - ANSWER How are palisade cells
adapted to their function in plants?
- Meristematic tissue, which is found wherever growth is occurring in plants such as at the tip of the
shoots and roots. - ANSWER Sources of plant stem cells?
- The chromatids assemble at the poles and the chromosomes uncoil and form chromatin again.
- The nuclear envelope reforms.
- Nucleolus becomes visible.
- Cytokinesis occurs again, resulting in four daughter cells in total. - ANSWER What happens
during Telophase 2 in Meiosis 2?
- The chromatids have reached the poles and the nuclear envelope reforms around the two new sets
of chromosomes. - ANSWER What happens during Telophase in mitosis?
- The chromosomes assemble at each pole.
- Nuclear membrane reforms.
- Chromosomes uncoil.
- ANSWER Alpha glucose?
- ANSWER Amino acid?
- ANSWER ATP?
- ANSWER Beta glucose?
- ANSWER Dexoyribose?
- ANSWER Fructose?
- ANSWER Nucleotide?
- ANSWER Phospholipid?
- ANSWER Purine?
- ANSWER Pyrimidine?
- ANSWER Ribose?
- ANSWER Sterol?
- ANSWER Structure of a fatty acid?
- ANSWER Triglyceride?
- ANSWER tRNA?
- A cleavage furrow forms around the middle of the cell and the cytoskeleton pulls the membrane
inwards.
- In plants, a cleavage furrow cannot form as they have a cell wall. Instead, vesicles align on the
metaphase plate, and fuse to the cell surface membrane, dividing the cell into two. -
ANSWER What happens during Cytokinesis?
- Centromeres divide, separating the chromatids as the spindle fibres shorten. -
ANSWER What happens during Anaphase in mitosis?
- Chromatin fibres coil and condense to form chromosomes.
- The nuclear envelope disintegrates.
- Spindle fibres form at either pole of the cell. - ANSWER What happens during Prophase in
mitosis?
- Chromosomes are moved by spindle fibres to form a plane along the equator of the cell. This is
known as the metaphase plate. - ANSWER What happens during Metaphase in mitosis?
- Chromosomes condense and become visisble again.
- In each cell, the nuclear envelope breaks down and spindle formation begins. -
ANSWER What happens during Prophase 2 in Meiosis 2?
,Biology AS Level, OCR
- Contain myofibrils (which contain contractile proteins) to enable the tissue to contract and move
the bone. - ANSWER How is muscle tissue adapted to its function of enabling bones to
move?
- Embryonic stem cells present at a very early stage of embryo development and are totipotent.
- Tissue (adult) stem cells are present through life from birth. They are found in bone marrow and are
multipotent, though it may be possible to trigger them to become pluripotent.
- Umbilical cords of newborn babies. - ANSWER Sources of animal stem cells?
- Flexible, due to well-developed microfilaments and microtubules in the cytoskeleton.
- Many lysosomes, containing enzymes for hydrolysis of pathogens.
- Many ribosomes/RER to make enzymes.
- Many mitochondria for ATP
- Many Golgi for production of lysosomes.
-Multi-lobed nucleus to help cell squeeze through small gaps. - ANSWER How are
neutrophils adapted to their function of defending the body against disease?
- Heart disease: heart attacks can cause permanent damage to muscle tissue in the heart.
- Type 1 Diabetes: stem cells may enable body to produce its own insulin-producing cells which are
not attacked by the immune system.
- Parkinson's: symptoms caused by death of dopamine-producing cells, so stem cells could help this.
- Alzheimer's: stem cells used to repair brain cells.
- Spinal injuries: Stem cell implants could help to repair damaged spinal cords. -
ANSWER Uses of stem cells in the future.
- Homologous pairs of chromosomes pair up along the metaphase plate.
- The orientation of each homologous pair is random and so this leads to independent assortment, as
any alleles can be made facing the poles. - ANSWER What happens during Metaphase 1 in
Meiosis 1?
- In both cells, the chromatids of the individual chromosomes are pulled to opposite poles after
division of the centromeres. - ANSWER What happens during Anaphase 2 in Meiosis 2?
- Individual chromosomes assemble on the metaphase plate in each cell.
- Due to crossing over, the chromatids are no longer identical so there is more independent
assortment happening here. - ANSWER What happens during Metaphase 2 in Meiosis 2?
- It contains fibres of elastin and collagen, which increases its flexibility.
- It is firm and composed of chondrocyte cells, which makes it appropriate for use between bones. -
ANSWER How is the tissue cartilage adapted to its function?
- It is composed of columns of sieve tube cells and parenchyma cells (used for food storage).
, Biology AS Level, OCR
- Sieve plates separate the cells, and the perforations allow food to flow quickly.
- Has many mitochondria as it is required to use active transport. - ANSWER How is the
phloem tissue adapted for its function in the transportation of organic nutrients through a plant?
- It is composed of vessel elements, which are long and thin dead cells.
- They contain lingin to strengthen and waterproof these dead cells, providing structural support. -
ANSWER How is the xylem tissue adapted for its function in the transportation of water
and minerals through a plant?
- It is formed of closely packed cells.
- It is usually covered by a waxy cuticle to reduce the loss of water.
- It contains stomata to allow gas exchange. - ANSWER How is the epidermis tissue adapted
to its function in plants?
- Large SA:V ratio for maximum oxygen uptake.
- Very small so can fit through capillaries.
- No nucleus/ organelles, so more room for haemoglobin.
- Highly flexible, to fit through narrower capillaries. - ANSWER How are erythrocytes
adapted to their function?
- Many mobile chloroplasts to absorb light energy and provide ATP.
- They are long and thin and form a continuous layer on the surface of the leaf so that light can reach
them.
- Large vacuole pushes chloroplasts to the edges of the cell.
- Thin cell wall increases the rate of diffusion of CO2. - ANSWER How are palisade cells
adapted to their function in plants?
- Meristematic tissue, which is found wherever growth is occurring in plants such as at the tip of the
shoots and roots. - ANSWER Sources of plant stem cells?
- The chromatids assemble at the poles and the chromosomes uncoil and form chromatin again.
- The nuclear envelope reforms.
- Nucleolus becomes visible.
- Cytokinesis occurs again, resulting in four daughter cells in total. - ANSWER What happens
during Telophase 2 in Meiosis 2?
- The chromatids have reached the poles and the nuclear envelope reforms around the two new sets
of chromosomes. - ANSWER What happens during Telophase in mitosis?
- The chromosomes assemble at each pole.
- Nuclear membrane reforms.
- Chromosomes uncoil.
